הלכה על סנהדרין 165:9

To not eat tevel: To not eat tevel - whether an Israelite or a priest - and that is a thing that tithes and priestly tithes have not been taken away from it, as it is stated (Leviticus 22:15), "And they shall not profane the consecrated things of the Children of Israel that they shall raise to the Lord." And the received (traditional) explanation comes about this (Sanhedrin 83a) that the verse is speaking about tevel. And the content of the verse is to say that they should not profane the consecrated things in their still being mixed with the non-sacred. And that is [why] the expression is [in] future tense - meaning to say that it has not yet been raised. And so [too], is it in the Gemara Sanhedrin 83a, "From where [do we know] about the one who eats tevel that he is [punishable by] death? As it is stated, 'And they shall not profane the consecrated things of the Children of Israel that they shall raise to the Lord' - the verse is speaking about those that will be raised in the future; such that we learn [a comparison of] 'profane' [and] 'profane' from priestly tithe," about which it is written (Numbers 18:32), "and the consecrated things of the Children of Israel you shall not profane and not die." And [the latter] is with the death penalty - as we wrote above (Sefer HaChinukh 280), from that which is written (Leviticus 22:9), "and die for it, since they profaned it," and adjacent to it, "And any foreigner shall not eat the holy." And they, may their memory be blessed, also said about this matter in the Gemara Makkot 16b, "Perhaps one is only liable for eating tevel from which no [gifts] were taken at all; but if the great priestly tithe was taken from [the produce], but not the tithe of the tithe, or the first tithe or the second tithe, or even if only the poor tithe [was not separated]; from where [is it derived] that there is a liability in the thing? [Hence] we learn to say, 'You may not eat in your gates' (Deuteronomy 12:17), and later it states, 'and they shall eat within your gates and be satisfied' (Deuteronomy 26:12). Just as there, it is poor tithe, here too, it is poor tithe - and the [Torah] states, 'You may not.'"