¶1ON REHEARING EN BANC
¶2Opinion
¶3This Court granted a rehearing en banc from a divided panel decision solely to determine whether the “ends of justice” exception to Rule 5A:18 should be invoked because an erroneous jury instruction may have deprived Joseph Hugh Campbell of a fair trial. Since a proper description of the elements *990of the offense was vital to ensure a fair trial, we hold that the “ends of justice” exception should be applied and we reverse the conviction. We leave unchanged the panel’s disposition of other issues originally raised on appeal. See Campbell v. Commonwealth, 13 Va. App. 33, 409 S.E.2d 21 (1991).
¶4I.
¶5During Campbell’s jury trial for forging a public record in violation of Code § 18.2-168, the jury was instructed as follows:
¶6JURY INSTRUCTION EIGHT
To act with the intent to defraud means to act with an evil intent, or with the specific intent to deceive or trick. It is sufficient if it was the intention of the defendant to frustrate the administration of a law or if his actions were prejudicial to, or a fraud upon, a Commonwealth or a governmental unit or tended to impair a governmental function.
¶7This was an incorrect statement of law. While the first sentence correctly defined intent to defraud, the second sentence effectively eliminated mens rea as an element of the offense. The use of the conjunction “or” in the second sentence allowed the jury to find Campbell guilty of forgery based solely on an action prejudicial to or tending to impair a governmental unit, and, thus, it allowed the jury to convict Campbell without finding that he had acted with intent to defraud. Intent to defraud is an element of the offense of forgery of public documents. See Hanbury v. Commonwealth, 203 Va. 182, 187, 122 S.E.2d 911, 914-15 (1961).
¶8The Commonwealth argues that Campbell did not preserve for appeal his objection to the jury instruction.
*991The prosecution must further prove beyond a reasonable doubt that the defendant acted with specific intent, that is that the defendant intended to inflict the specific harm prohibited by the offense.
To establish specific intent the prosecution must prove that the defendant knowingly did an act which the law forbids, purposely intending to violate the law.
It is not enough, therefore, to believe beyond a reasonable doubt that the defendant purposely did an act wrongful in itself; the prosecution must also prove beyond a reasonable doubt that the defendant intended to impose a harm upon another in a way prohibited by law. Such intent may be determined from all the facts and circumstances surrounding the case.
¶9Because the granted Instruction Eight purported to define “intent to defraud” and the refused Instruction N addressed “specific intent,” we cannot say that Campbell’s refused instruction “propound [ed] the contrary theory to one set forth in [the] granted instruction.” Id. at 498, 229 S.E.2d at 885.
¶10Campbell claims error because Instruction Eight incorrectly defined “intent to defraud.” However, at trial, Campbell objected to the instruction only:
on the grounds that [the instruction] fails to point out that intent to defraud means to deprive under the circumstances of this case one of tangible rights.
¶11Although the objection raised at trial is not the same as the issue raised on appeal and although Rule 5A:18 generally precludes this Court from entertaining issues that were not properly brought to the attention of the trial judge, we review this issue to attain the “ends of justice.” Rule 5A:18.
¶12II.
¶13“[W]hen a principle of law is vital to a defendant in a criminal case, a trial court has an affirmative duty properly to instruct a jury about the matter.” Jimenez v. Commonwealth, 241 Va. 244, 250, 402 S.E.2d 678, 681 (1991). That duty arises even when “trial counsel neglected to object to the instruction.” Id. at *992248, 402 S.E.2d at 679. Obviously, the proper description of the elements of the offenses is vital to a defendant. Attaining the “ends of justice” requires correction of an instruction which allows a jury to convict a defendant without proof of an element of a crime. Instruction Eight was so defective that it allowed the jury to convict Campbell of forgery even if the jury concluded that Campbell lacked an intent to defraud. Intent to defraud, however, is a necessary element of forgery. Fitzgerald v. Commonwealth, 227 Va. 171, 173, 313 S.E.2d 394, 395 (1984).
[A]n essential of the due process guaranteed by the Fourteenth Amendment [is] that no person shall be made to suffer the onus of a criminal conviction except upon sufficient proof — defined as evidence necessary to convince a trier of fact beyond a reasonable doubt of the existence of every element of the offense.
¶14Jackson v. Virginia, 443 U.S. 307, 316 (1979) (emphasis added). The jury cannot be said to have reached the level of certitude constitutionally required to convict when the jury was instructed that it could find the defendant guilty even though all of the elements of the offense had not been proved beyond a reasonable doubt.
Unless [the appropriate] elements are defined by instructions available to the members of the jury during their deliberation, they cannot properly determine whether the Commonwealth has carried its burden. . . . “It is always the duty of the court at the proper time to instruct the jury on all principles of law applicable to the pleadings and the evidence,” and “a correct statement of the law applicable to the case, when the law is stated, ... [is one of the] essentials of a fair trial.”
¶15Dowdy v. Commonwealth, 220 Va. 114, 116, 255 S.E.2d 506, 508 (1979) (citations omitted); see also Darnell v. Commonwealth, 6 Va. App. 485, 488, 370 S.E.2d 717, 719 (1988).
¶16The instructions given by the trial judge relieved the Commonwealth of its burden to prove criminal intent by improperly informing the jury that it could convict Campbell simply if the jury found a prejudicial effect or impairment on a governmental function. Thus, the jury could have believed Campbell’s defense — that he had no intent to defraud because his statement to the clerk *993who changed the record was only intended as a joke — and yet convicted him by finding that his conduct “tended to impair a governmental function.” This occurrence deprived Campbell of the process that he was due.
“There is always in litigation a margin of error, representing error in factfinding, which both parties must take into account. Where one party has at stake an interest of transcending value - as a criminal defendant his liberty - this margin of error is reduced as to him by the process of placing on the other party the burden of . . . persuading the factfinder at the conclusion of the trial of his guilt beyond a reasonable doubt.”
¶17In re Winship, 397 U.S. 358, 364 (1970) (quoting Speiser v. Randall, 357 U.S. 513, 525-26 (1958)). This doctrine, which is the cornerstone of our system of criminal justice, “requires more than simply a trial ritual.” Jackson, 443 U.S. at 316-17.
¶18The Commonwealth misconstrues the holding of Mounce v. Commonwealth, 4 Va. App. 433, 357 S.E.2d 742 (1987), when it claims the “ends of justice” provision requires reversal only if the error “invariably works a miscarriage of justice.” (emphasis added). In Brown v. Commonwealth, 8 Va. App. 126, 380 S.E.2d 8 (1989), this Court emphasized that, “[ajlthough the ends of justice exception is narrow and is to be used sparingly, [the Court will not place] too restrictive an interpretation upon Mounce.” Id. at 132, 380 S.E.2d at 11. Specifically, the Court explained:
The language in Mouncethat to avail himself of the rule the defendant had to affirmatively show that “a miscarriage of justice [has] occurred, not . . . that a miscarriage might have occurred” requires that the error be clear, substantial and material.
¶19Id.Unquestionably, the error in instructing this jury meets that standard. No amount of sophistry can avoid the hypothesis that the jury believed the defense testimony, that Campbell lacked an intent to defraud, yet convicted him because of the incorrectly drawn instruction that authorized conviction based on a finding that his conduct “tended to impair a governmental function.”
¶20*994The resolution of this dilemma is not found in weighing Campbell’s hypothesis of innocence against the quantum of proof that the Commonwealth offered in support of guilt. If the jury believed the testimony of Campbell, as it was entitled to do, the quantum of contrary evidence was irrelevant.
¶21Traditional principles dictate, both in the civil and criminal law, that the determination of a witness’ credibility is within the fact finder’s exclusive purview because he has the best opportunity to observe the appearance and demeanor of the witness.
The credibility of witnesses is a question exclusively for the jury, and where a number of witnesses testify directly opposite to each other, the jury is not bound to regard the weight of the evidence as equally balanced, they have the right to determine from the appearance of the witnesses on the stand, their manner of testifying, and their apparent candor and fairness, their apparent intelligence, or lack of intelligence, and from all the other surrounding circumstances appearing on the trial, which witnesses are more worthy of credit, and to give credit accordingly.
¶22Goodyear Tire & Rubber Co. v. Pierce, 5 Va. App. 374, 381, 363 S.E.2d 433, 437 (1987) (quoting Zirkle v. Commonwealth, 189 Va. 862, 870, 55 S.E.2d 24, 29 (1949)).
¶23Campbell is entitled to have a jury trial in which “ ‘the law has been clearly stated [to the jury] and ... the instructions cover all issues which the evidence fairly raises.’ ” Darnell, 6 Va. App. at 488, 370 S.E.2d at 719. A fundamental hallmark of a fair trial is that “instructions . . . should inform the jury as to the law of the case applicable to the facts in such a manner that [the jury] may not be misled.” Cooper v. Commonwealth, 2 Va. App. 497, 500, 345 S.E.2d 775, 777 (1986).
¶24When an instruction allows a jury to convict a defendant without proof of an essential and necessary element of the charged offense, the Commonwealth is not entitled to an appellate affirmance based solely on application of Rule 5A:18. If we give effect to the presumption that a jury follows the trial judge’s instruc*995tions, LeVasseur v. Commonwealth, 225 Va. 564, 589, 304 S.E.2d 644, 657 (1983), cert. denied, 464 U.S. 1063 (1984), it is not appropriate for this Court to affirm a conviction when the jury could have convicted the defendant for otherwise innocent behavior. “It is elementary that a jury must be informed as to the essential elements of the offense; a correct statement of the law is one of the ‘essentials of a fair trial.’ ” Darnell, 6 Va. App. at 488, 370 S.E.2d at 719 (quoting Dowdy, 220 Va. at 116, 255 S.E.2d at 508).
¶25The error in this case was patently harmful and was “so contrary to fundamental notions of justice that to permit it to pass uncorrected would seriously undermine the integrity of our judicial system.” Brown, 8 Va. at 133, 380 S.E.2d at 11. “The state’s interest in prevailing at trial and upholding the verdict on appeal must be tempered by its duty to work for a just, fair and accurate adjudication of criminal cases.” Id.at 133 n.3, 380 S.E.2d at 11 n.3.
¶26For these reasons we reverse the conviction and remand for a new trial.
¶27Reversed and remanded.
¶28Koontz, C.J., Bray, J., and Elder, J., concurred.
¶29 Rule 5A:18 provides that:
No ruling of the trial court . . . will be considered as a basis for reversal unless the objection was stated together with the grounds therefor at the time of the ruling, except for good cause shown or to enable the Court of Appeals to attain the ends of justice.
¶30concurring.
¶31Although I concur with the majority opinion, I write separately to explain why, in my opinion, the contemporaneous objection rule does not bar a reversal in this appeal. By writing separately, I seek to express those principles that underlie my decision and urge the uniform application of these principles to like cases.
¶32The contemporaneous objection rule embodied in Rule 5A:18 is not without exception. Even where an objection is not stated, an error may be the basis for reversal (1) “for good cause shown,” or (2) “to enable the Court of Appeals to attain the ends of justice.” Rule 5A:18. In addition, where “a party has no opportunity to object to a ruling or order at the time it is made,” the party’s failure to object shall not prejudice him or her on appeal. Code § 8.01-384(A). Thus, three reasons may exist for addressing an assertion of error on appeal, even if a timely objection is not made at trial.
¶33*996“[G]ood cause” relates to the reason why an objection was not stated at the time of the ruling. See Murray v. Carrier, All U.S. 478, 488-89 (1986); Townes v. Commonwealth, 234 Va. 307, 319, 362 S.E.2d 650, 656-57 (1987), cert. denied, 485 U.S. 971 (1988) (pro se representation is not good cause for failing to object); Snurkowski v. Commonwealth, 2 Va. App. 532, 536, 348 S.E.2d 1, 3 (1986) (futility of an objection is not good cause for failing to object). Similarly, the lack of an “opportunity to object” also relates to the reason why an objection was not made at the time of the ruling. Jones v. Commonwealth, 194 Va. 273, 280, 72 S.E.2d 693, 697 (1952) (counsel “taken by surprise” by trial court’s response to question from jury); Mason v. Commonwealth, 1 Va. App. 339, 346, 373 S.E.2d 603, 606 (1988) (counsel “taken by surprise” at trial court’s instruction to the jury). Thus, the statutory exception is subsumed under the “good cause” exception because both relate to the reason why an objection was not timely made.
¶34The “ends of justice” exception, on the other hand, addresses the effect of the error, not the reason for the failure to object to the error. The purpose underlying the contemporaneous objection rule is helpful in understanding the “ends of justice” exception.
¶35The rule serves “to avoid unnecessary appeals, reversals and mistrials by allowing the trial judge to intelligently consider an issue and, if necessary, to take corrective action.” Campbell v. Commonwealth, 12 Va. App. 476, 480, 405 S.E.2d 1, 2 (1991) (en banc). In some instances, this goal is already assured by a party’s incentive to object to an error in order to increase the opportunity for a favorable disposition and, also, because of the party’s own desire to avoid a retrial and its accompanying expense and anxiety. Thus, need for applying the rule is greater where a party’s incentive to object is not present.
¶36For example, little incentive exists for a defendant to complain at trial about the legal insufficiency of the case presented against the defendant. If the case is legally insufficient and the verdict of the trier of fact is for the defendant, all is well. If, on the other hand, the verdict is against the defendant, the defendant can appeal and, but for the contemporaneous objection rule, obtain reversal because of the legal insufficiency of the action. Upon reversal, the cause will be dismissed without the possibility of a retrial. Thus, except for the contemporaneous objection rule, the only in*997centive prompting a defendant to challenge the sufficiency of the evidence at trial is the cost and delay of an appeal. In fact, the threat that the trial court might allow the Commonwealth to reopen its case in response to such a challenge would be a disincentive to raise the issue at trial, absent the contemporaneous objection rule. Thus, only when the record affirmatively shows that a criminal defendant “has been convicted of a crime of which under the evidence he could not properly be found guilty,” does the “ends of justice” exception permit an appellate court to review the legal sufficiency of the evidence underlying the conviction where the issue was not raised at trial. Ball v. Commonwealth, 221 Va. 754, 758-59, 273 S.E.2d 790, 793 (1981); see also Momee v. Commonwealth, 4 Va. App. 433, 436, 357 S.E.2d 742, 744 (1987).
¶37However, the “ends of justice” exception is not always so restrictively applied. See Cooper v. Commonwealth, 205 Va. 883, 889, 140 S.E.2d 688, 692-93 (1965) (admission without objection of unconstitutionally obtained confession); Glasgow v. Peatross, 201 Va. 43, 47, 109 S.E.2d 135, 138 (1959) (“confusing and erroneous” instruction given without objection); Brown v. Commonwealth, 8 Va. App. 126, 132, 380 S.E.2d 8, 11 (1989) (defendant’s sentence based on pre-sentence report describing a different burglary from that for which he was convicted). Where a party’s desire for a favorable outcome and desire to avoid a retrial act as incentives for the party to object to adverse rulings, the need for strict adherence to the contemporaneous objection rule, although not eliminated, is less compelling. In those instances, an error may be the basis for reversal, when not objected to, if it is “clear, substantial and material.” Brown, 8 Va. App. at 132, 380 S.E.2d at 11. To allow an error meeting those criteria “to pass uncorrected would seriously undermine the integrity of our judicial system.” Id. at 133, 380 S.E.2d at 11.
¶38To be “clear” the error must be apparent under existing statutory or case law without the necessity of further judicial interpretation and must not have been acquiesced in, either expressly or impliedly, by the complaining party. See Cooper, 205 Va. at 889, 140 S.E.2d at 692-93. A trial judge may reasonably rely on the parties to bring to the trial judge’s attention unresolved questions of law and may assume that one who does not object to certain rulings, for example the introduction of patently inadmissible evi*998dence, acquiesces in the rulings for his or her own benefit.
¶39To be “substantial” the error must affect an essential element of the trial. See Glasgow, 201 Va. at 47, 109 S.E.2d at 138. It must affect a part of the trial without which the trial could not have properly been conducted.
¶40Finally, to be “material” the error must be important enough to affect the outcome of the trial. Otherwise, the error would be harmless. See Lavinder v. Commonwealth, 12 Va. App. 1003, 1005, 407 S.E.2d 910, 911 (1991) (en banc).
¶41In this case, because the error was in the content of an instruction given, the effect of a reversal is not a dismissal but a remand for a new trial. The defendant, consequently, had an incentive to object to the error, as he did (albeit on other grounds), without being prompted by the contemporaneous objection rule. Therefore, the “ends of justice” exception applies to this error if it is “clear, substantial and material.”
¶42The error in this case was “clear.” It is undisputed that the instruction complained of on appeal allowed the jury to find the defendant guilty if it found that his action was prejudicial to a governmental unit or tended to impair a governmental function without finding that he did so with an intent to defraud, an element of the crime with which he was charged. The instruction was contrary to existing law. See Hanbury v. Commonwealth, 203 Va. 182, 187, 122 S.E.2d 911, 914-15 (1961). The defendant objected to the instruction at trial, although on different grounds; he did not acquiesce, even impliedly, in the instruction.
¶43The error was “substantial” in that it affected an essential element of the trial — the instructions to the jury on the elements of the crime charged. Without being told what the elements of the crime were, the jury could not have properly decided the case.
¶44Finally, it was “material.” If the jury followed the instruction, as we must assume it did, it could have found the defendant guilty without having found that he committed the crime. The instruction did not conflict with a correct instruction that might have caused the jury to ignore it. It was, instead, an incorrect attempt to further define the element of intent required. Thus, the jury had no reason to question its applicability.
¶45*999For these reasons, I join in the majority’s opinion and its decision to reverse the defendant’s conviction and remand the proceeding for a new trial.