Leviticus 23:12
And ye shall offer that day when ye wave the sheaf an he lamb without blemish of the first year for a burnt offering unto the LORD. And ye shall offer that day when ye wave the sheaf an he lamb without blemish of the first year for a burnt offering unto the LORD.
The waving commanded in the verse belonged to the second day of the seven days' feast of unleavened bread that followed the Passover. That seven-day feast was bounded by holy convocations on its first and seventh days, on which no servile work was to be done. The sheaf to be waved was of barley, the earliest grain in Palestine, which was just beginning to ripen as the feast opened.
The priest waved that first-fruits sheaf before the altar of God as an acknowledgment that all belonged to Him. Not until this ceremony had been performed was the harvest to be gathered.