Deuteronomy 26:12-13

12“Every third year you must offer a special tithe of your crops. In this year of the special tithe you must give your tithes to the Levites, foreigners, orphans, and widows, so that they will have enough to eat in your towns.

13Then you must declare in the presence of the Lord your God, ‘I have taken the sacred gift from my house and have given it to the Levites, foreigners, orphans, and widows, just as you commanded me. I have not violated or forgotten any of your commands.