Deuteronomy 15:10

15:10 You must by all means lend to him and not be upset by doing it, for because of this the Lord your God will bless you in all your work and in everything you attempt.

Deuteronomy 25:5

Respect for the Sanctity of Others

25:5 If brothers live together and one of them dies without having a son, the dead man’s wife must not remarry someone outside the family. Instead, her late husband’s brother must go to her, marry her, and perform the duty of a brother-in-law.