Halakha Imamat 23:14: Mishneh Torah, Daily Offerings and Additional Offerings, Mishneh Torah, Foundations, Mishneh Torah, Forbidden Foods & Kitzur Shulchan Arukh

... And they learned from the oral tradition that it is not Shabbat (that "from the morrow of the Shabbat" is not the weekly Shabbat) but rather the holiday [of Passover]. And so did the prophets and the high courts see in each and every generation, that they would wave the omer on the sixteenth of Nissan - whether it was on a weekday or on Shabbat. And behold, the Torah states (Leviticus 23:14), "Until that very day, you shall eat no bread or parched grain or fresh ears." And [in the Prophets, it] states (Joshua 5:11), "On the day after the Passover offering, on that very day, they ate of the produce of the country, unleavened bread and parched grain." And if you should say that this Passover came out on Shabbat - like the fools imagine - how could Scripture make the license to eat the new grain dependent on something which is not the main point nor the cause, but rather just happenstance. Rather, since it made it dependent on the morrow of Passover, it is a clear matter that the morrow of Passover is the cause of the license [to eat] the new grain; and we are not concerned about which day of the week it is.

It is a clear and manifest principle concerning the Torah that as a Law it is permanently established forever and evermore; and that it is not subject to mutibility, nor to diminution, nor to amendment; for it is said: "All this word which I command you, that shall ye observe to do; thou shalt not add thereto, nor diminish from it" (Ibid. 13.1); and it is further said: "But the things that are revealed belong unto us and to our children forever, that we may do all the words of this law" (Ibid. 29.28). Herefrom we learn that according to all the words of the Torah we are commanded to do forever. It is, moreover, said: "a statute forever throughout your generations" (Num. 15.15); and again it is said:¹See Baba Mezi’a 59. C. "It is not in heaven" (Deut. 30.12); herefrom we learn that no prophet is thereafter permitted to make any innovation. Therefore, should a man rise up, whether he be from among the Gentiles or whether from among Israel, and deliver a token and perform a miracle saying, that God hath sent him to add a commandment, or to diminish a commandment, or to interpret a certain commandment of among the commandments with such interpretation as we have not heard by tradition from Moses; or he said, that these commandments with which Israel was charged are not forever and throughout all generations, but that they were commandments in keeping with those times only, behold him, he is a false prophet, seeing that he came to deny the prophecy of Moses; and his punishment is death by strangulation, because he wilfully spoke in the name of God concerning that which He did not charge him; for He, blessed is He! commanded Moses, saying, that this enactment was "unto us and unto our children forever" (Deut. 29.28); and, "God is not a man that He should lie" (Num. 23.19).

Unter jungem Getreide ist zu verstehen, dass man von der frischen Ernte der fünf Getreidearten, bevor das Omer (Getreideopfer) am sechszehnten des Monats Nissan dargebracht wurde, nicht essen durfte, denn es heißt: »Brot, gedörrte und geriebene Ähren, sollt ihr nicht essen« (Lev. 23:14), Wer das Quantum einer Olive von diesem frischen Getreide vor der Darbringung des Omers aß, erhielt laut Vorschrift der Tora, aller Zeiten und aller Orten, sowohl im gelobten Lande als im Auslande, sowohl während des Bestehens des Tempels, als nach dieser Zeit, die Geißelung; der Unterschied bestand nur darin, dass, solange der Tempel besteht, das frische Getreide in Jerusalem alsbald nach der Darbringung des Omers zu essen erlaubt wurde; seitdem der Tempel nicht existiert, ist es laut Vorschrift der Tora den ganzen sechszehnten Nissan hindurch verboten, frisches Getreide zu essen; jetzt aber, wo man zwei Feiertage feiert, ist es nach der Bestimmung der Weisen auch den ganzen siebenten Nissan hindurch verboten.