Exodus 29:1-3

This is what you are to do to make them holy, to do the work of priests to me: Take one young ox and two male sheep, without any mark on them, And unleavened bread, and unleavened cakes mixed with oil, and thin unleavened cakes on which oil has been put, made of the best bread-meal; Put these in a basket and take them, with the ox and the two sheep.