מצוות חלה

(2) It is from the roots of the commandment [that it is that] since the sustenance of a person is through food and most of the world will be sustained with bread, the Omnipresent desired to give us merit with a constant commandment in our bread, so that blessing should rest upon it through the commandment; and through it, we will receive merit for our souls. And [hence] it turns out that the dough is food for our body and food for our soul. Additionally, [it is] in order that the servants of God, those that are constantly involved in His service - and these are the priests - should be sustained without any toil at all. Whereas with the tithe of the threshing floor there is labor for them, to pass the grain through the sieve and to grind it; here, their ration will come to them without any pain whatsoever.