הלכה על פסחים 45:19

That no foreigner eat priestly tithe: That no foreigner (non-priest) eat priestly tithe, as it is stated (Leviticus 22:10), "And any foreigner shall not eat the holy." And the received (traditional) understanding (Pesachim 23a) came that this "holy" is only the priestly tithe and anything that is called priestly tithe (terumah), but it does not come here to warn about other types of holy things. And that which is also called priestly tithe is the first fruits, as they, may their memory be blessed, expound from the tradition (Pesachim 36b), "'And the terumah of your hand' (Deuteronomy 12:17) - these are the first fruits."