Numbers 15:17-21

Again the LORD spoke to Moses, saying, “Speak to the children of Israel, and say to them: ‘When you come into the land to which I bring you, then it will be, when you eat of the bread of the land, that you shall offer up a heave offering to the LORD. You shall offer up a cake of the first of your ground meal as a heave offering; as a heave offering of the threshing floor, so shall you offer it up. Of the first of your ground meal you shall give to the LORD a heave offering throughout your generations.