Exodus 29:1-4

“Now this is what you shall do to them to consecrate them to minister as priests to Me: take one young bull and two rams without blemish, and unleavened bread and unleavened cakes mixed with oil, and unleavened wafers spread with oil; you shall make them of fine wheat flour. You shall put them in one basket, and present them in the basket along with the bull and the two rams. Then you shall bring Aaron and his sons to the doorway of the tent of meeting and wash them with water.