Commentary for Leviticus 23:20

והניף הכהן אתם... תנופה AND THE PRIEST SHALL WAVE THEM [WITH THE BREAD OF THE FIRSTLINGS] FOR A WAVE OFFERING — This teaches us that they (the offerings) require the waving whilst they are still living. One might think that all of them (the seven lambs mentioned in v. 18) have to be waved! It, however, states על שני כבשים “[and the priests shall wave them… upon the two lambs]” (cf. Menachot 62a).

[While] alive. We derive this from the gezeroh shovoh “them,” “them.” It is written here, “The kohein shall wave them,” and it is written elsewhere, in parshas Metzora (14:12), “And wave them [the lamb and log of oil] as a wave-offering before Hashem.” Just as there [it is when they are] alive, for it is written afterwards (verse 13), “He shall slaughter the lamb,” so here too while they are alive. Re’m, however, explains: Because [We derive that the animal is waved while still alive] since it says regarding the peace-offering of an individual (above 7:34), “Because the breast waveoffering and the thigh [that is] the uplifted portion I have taken from Bnei Yisroel, from their peace-offerings (זבחי שלמיהם),” which implies the plural form. It should have said this in the singular form because it is talking of the peace-offering of an individual. This [plural expression] teaches that public peace-offerings too require waving. If so, why does the verse here need to write “The kohein shall wave them [the sheep peace-offerings] along with the bread of the first-fruit-offering as a wave-offering before Hashem?” It must be to teach the waving of the public peace offerings is [also] while they are still alive. This is [derived] in Perek Kol Hamenachos (Menachos 62a).

והניף הכהן אותם, “the priest will wave them;” the two sheep for the Shavuot festival.