N.H. Rev. Stat. Ann. § 92:2

No person chosen or appointed to any public office or to any position where an oath is required, under any law, shall exercise such office or position or perform any act therein until he shall make and subscribe the oath or declaration as prescribed by part 2, article 84 of the constitution of New Hampshire, and any such person who violates said oath after taking the same shall be forthwith dismissed from the office or position involved.