Exodus 29:22-24

Then take the fat of the sheep, the fat tail, the fat covering the insides, and the fat joining the liver and the two kidneys with the fat round them, and the right leg; for by the offering of this sheep they are to be marked out as priests: And take one bit of bread and one cake of oiled bread and one thin cake out of the basket of unleavened bread which is before the Lord: And put them all on the hands of Aaron and of his sons, to be waved for a wave offering before the Lord.