3,275. Biblical vs. Rabbinic Terumah
Terumos 6:2
Terumah required under Biblical law may only be eaten by a confirmed kohein; those who are kohanim by presumption may only eat terumah required under Rabbinic law. Ritually clean terumah, whether the terumah gedolah or terumas maaser, whether required under Biblical or Rabbinic law, is only given to a kohein who is learned in Torah. This is because it is prohibited to eat ritually unclean terumah and unlearned people are under a presumption of ritually impure. For this reason, one may give ritually unclean terumah (which must be burned) to any kohein he chooses.
Terumos 6:3
If an Israelite woman marries a kohein, even if she’s only three years and one day old, she may eat terumah, as well as the breast and thigh (the kohein’s portion of peace offerings). Under Biblical law, she may eat these things as soon as she is betrothed to the kohein, but the Sages prohibited doing so until after the chuppah. This is because a betrothed woman still lives in her father’s house, so there’s concern that she might give her father and brother terumah to eat.