פירוש על ויקרא 22:16

והשיאו אותם means, and they (the priests) would burden themselves with sin, באכלם את קדשיהם WHEN THEY (the non-priests) EAT THEIR HOLY THINGS which have been set apart for the purpose of heave-offering and have thereby become holy and forbidden to them. [Onkelos who translated באכלם את קדשיהם by “when they (the priests) eat them in their uncleanness” has translated it thus quite unnecessarily] (But cf. Rashi on Sanhedrin 90b).

והשיאו אותם עון אשמה, they themselves, when they declared the items in question (for instance t’rumah) as sacred cause themselves to become guilty in the event they would trespass and make profane use of them. The Torah does not allow you to apply the principle הפה שאסר הוא הפה שהתיר, that just as one may declare something forbidden, the same person can also declare it as allowed. (D’mai,6,11) The reason why we cannot apply this principle in this case is אני ה' מקדשו, seeing that G’d Himself elevated this item to a status of holiness, a mere mortal, even the donor, cannot remove such sanctity at his own discretion.

והשיאו אותם עון אשמה, "and so cause them to bear the sin which brings guilt, etc." The meaning of the verse is that if the guilty person did not make restitution of both the value of the amount of holy things consumed plus the 20%, the parameter of the sin will grow wider so that it will be classified as if it had been committed intentionally (i.e. עון). The justification for this is that when one fails to correct a sin inadvertently committed although one has been given an opportunity to correct it, the original sin becomes so much more serious. The word והשיאו is equivalent to ינשאו "they will have to bear them;" הם i.e. the combined sins. The Torah adds: באכלם את קדשיהם, the sin will now be considered not merely failure to pay the penalty but it will be considered as if they had eaten their holy things on purpose. Compare my comments on the last verse.