Mont. Code Ann. § 71-1-229

The purchaser of land at mortgage foreclosure is not entitled to the possession of the land as against the execution debtor during the period of redemption allowed by law while the execution debtor personally occupies the land as a home for the execution debtor and the debtor's family. It is unlawful to insert in any mortgage of real estate any provision intended to constitute a waiver by the owner of real estate personally occupying land as a home for the owner and the owner's family of the provision of this section or any provision intended to give the mortgagee possession of the land or premises prior to foreclosure upon default of tax, principal, or interest payments. The intention of this section is to ensure to the owner the possession of the land prior to foreclosure and during the year of redemption.