“Yahweh spoke to Moses. Speak to the people of Israel and say to them, when you enter the land that I am giving you and you reap its harvest, you shall bring the sheaf of the first fruits of your harvest to the priest. He shall raise the sheaf before Yahweh, that you may find acceptance. On the day after the Sabbath the priest shall raise it. On the day when you raise the sheaf, you shall offer a lamb a year old without blemish as a burnt offering to Yahweh. The grain offering with it shall be two-tenths of an ephah of choice flour mixed with oil, to be offered by fire as a pleasing odor to Yahweh. The drink offering with it shall be of wine, one-fourth of a hin. You shall eat no bread, parched grain, or fresh ears until that very day, until you have brought the offering to your God. It is a statute forever throughout your generations in all your settlements.”
The next festival is the first harvest. This is clearly for the time when you enter the land that Yahweh was giving them, not now. You have to bring the first fruits of your harvest to the priest. This would be after the feast of the unleavened bread, probably the barley harvest. At that time you present a burnt offering of a year old lamb without blemish and the grain offering of 20% of a bushel of choice flour. A bushel is about the same as an ephah. You also bring a drink offering of wine, a quarter of a hin. This is the first mention of wine as a gift offering. A hin is about 8 quarts so that this would be about 2 quarts of wine. You do not eat anything until you have brought the offering to God. This is once again a statute forever in all your settlements.