Deuteronomy 14:28
At the end of every three years thou shalt bring forth all the tithe of thine increase in the same year, and shalt lay it up within thy gates:
Deuteronomy 14:22
Thou shalt surely tithe all the increase of thy seed, that which cometh forth from the field year by year.
Amos 4:4
Come to Beth-el, and transgress; to Gilgal, and multiply transgression; and bring your sacrifices every morning, and your tithes every three days;
Deuteronomy 26:12-15
When thou hast made an end of tithing all the tithe of thine increase in the third year, which is the year of tithing, then thou shalt give it unto the Levite, to the sojourner, to the fatherless, and to the widow, that they may eat within thy gates, and be filled.