John Gill Commentary Exodus 29:26

"And thou shalt take the breast of Aaron`s ram of consecration, and wave it for a wave-offering before Jehovah: and it shall be thy portion." — Exodus 29:26 (ASV)

And you shall take the breast of the ram of Aaron's
consecrations
The ram being slain and cut to pieces, this part is particularly disposed of:

and wave it for a wave offering before the Lord;
in the manner before described:

and it shall be your part:
the part of Moses, he officiating now as a priest; and we find accordingly in later times that this part of the sacrifice belonged to the priest, (Leviticus 7:31) .