Mishpatim: Chapter 19
Concerning tithing

The precept discussed here is to offer the first fruit, then to confess by the first fruit and later to publicly announce the crop by tithing. The question that arises is whether to tithe before or after the fruits and grains are formed. The children of Yisrael are compared to the tree and to grain; they are called a large powerful tree with sustenance for all within it. The Torah is sustenance on high and prayer is sustenance for those below. Even the sustenance for angels comes only through Yisrael because of their Torah study and their following of the precepts. The Torah is compared to water and to fire, both of which are required to ripen fruit (the sun being fire). Those who study the Torah, the Tree of Life, follow the blossoming, and so they are tithed because Chochmah dwells in them.