Leviticus 23:9-11

And the Lord said to Moses, Say to the children of Israel, When you have come to the land which I will give you, and have got in the grain from its fields, take some of the first-fruits of the grain to the priest; And let the grain be waved before the Lord, so that you may be pleasing to him; on the day after the Sabbath let it be waved by the priest.