They must eat those things by which atonement was made for their ordination and consecration. But no outsider may eat them, because these things are sacred.
The ceremonies for consecrating Aaron and his sons had to be set down in detail so that they themselves would grasp the weight of what God called them to, and the people would learn to honor the office and keep their hands off it. The Hebrew word for consecrating means filling the hand, which tells us ministers have their hands full, no time for trifling, their work is so great and constant.
AI summary
Commenting on Exodus 29:1-37
Aaron and his sons ate the sacrifice because they themselves needed atonement for their own sins, which Christ did not; their eating foreshadows receiving Christ's atonement by faith. But no one outside the priesthood could eat these holy things, for they were set apart to sacred service alone.
AI summary
And they shall eat those things wherewith the atonement was made, to consecrate [and] to sanctify them: but a stranger shall not eat [thereof], because they [are] holy. (l) That is, by the sacrifices.