Leviticus 23:14
And ye shall eat neither bread, nor parched corn, nor green ears, until the selfsame day that ye have brought an offering unto your God: it shall be a statute for ever throughout your generations in all your dwellings. And ye shall eat neither bread, nor parched corn, nor green ears, until the selfsame day that ye have brought an offering unto your God: it shall be a statute for ever throughout your generations in all your dwellings.
The year's firstfruits were to be presented before God on the second day of the seven days' feast of unleavened bread. The offering was a sheaf of barley, the earliest grain in Palestine and then beginning to ripen, which the priest waved before the altar as an acknowledgment that the whole harvest belonged to Him. No part of the harvest was to be gathered until after that waving ceremony had been performed.