Halakhah sa Levitico 23:11: Mishneh Torah, Sheqel Dues & Mishneh Torah, Daily Offerings and Additional Offerings

In the sabbatical year – which is [a time when all produce is] ownerless – the court hires [agents] to guard a little of the natural growth, that it should grow in order that they can bring the omer from them; [as well as] the two breads, which may only come from the new [grain]. And these guards take their wages from the appropriation of the chamber.

... 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.