3,249. Leaving Produce to Tithe for Other Produce
Terumos 3:21
If a Levi had first tithe from which terumas maaser had not been taken and he left it so that he could repeatedly take terumas maaser for other produce from it while it was still untithed, then what he did is done (i.e., it worked). This is inferred from Numbers 18:24, which says, “the tithes of the children of Israel from which they will separate terumah to Hashem...,” meaning that he can use the entire tithe as terumah.
Terumos 3:22
Let’s say that someone took terumas maaser first, after which he left the produce so that he could repeatedly take terumas maaser for other produce from it until it’s all terumas maaser, which he would then give to a kohein. In such a case, his actions are ineffective. This is learned from Numbers 18:29, which says, “The sacred part of it.” When the sacred part (terumas maaser) is in it, it can be made terumah for other produce; once the sacred part is no longer in it, it cannot. Similarly, if a person puts aside crops from which to take terumah gedolah, they must be untithed of terumah. If he puts aside crops from which to take maaser, they must be untithed of maaser.