Reference for Bava Batra 285:5
שאני התם דמדאורייתא תרומה מעלייתא היא
— There it is different; for Biblically it<span class="x" onmousemove="('comment',' The bitter portion of the cucumber. ');"><sup>12</sup></span> is perfect <i>terumah</i>,' for R. Elai said, 'Whence [is it inferred] that if one separates a heave-offering from an inferior quality for the [redemption of] a superior quality that his offering is valid? For it is said. And ye shall bear no sin by reason of it, seeing that ye have set apart from it the best thereof.<span class="x" onmousemove="('comment',' Num. XVIII, 32. ');"><sup>13</sup></span> [From this it is to be inferred that if you do not set apart from the best, but of the worst, you shall bear sin]; if, [however, the inferior quality] does not become consecrated, why should there be any bearing of sin!<span class="x" onmousemove="('comment',' Surely no wrong has been done, since his action is null and void, and he has to give another heave-offering. ');"><sup>14</sup></span>