Halakhah sa Deuteronomio 20:2: Mishneh Torah, Positive Mitzvot

To anoint a special priest (to address the soldiers) in a war, as it is said, “And it shall be when ye are come nigh unto the battle, that the priest shall approach (and speak unto the people)” (Deut. 20:2).

To lend to a poor person, as it is said, “If thou lend money to any of my people” (Ex. 22:24). The word “If” here is not to be taken as permissive, but obligatory, as it is said, “And thou shalt surely lend him (sufficient for his need)” (Deut. 15:8).