Leviticus 23:11

He shall wave the sheaf before the Lord — In the name of the whole congregation, which as it were sanctified to them the whole harvest, and gave them a comfortable use of all the rest. For then we may eat our bread with joy, when God hath accepted our works. And thus should we always begin with God; begin our lives with him, begin every day with him, begin every work and business with him: seek ye first the kingdom of God. The morrow after the sabbath — After the first day of the feast of unleavened bread, which was a sabbath or day of rest, as appears from Leviticus 23:7, or upon the sixteenth day of the month. And this was the first of those fifty days, in the close whereof was the feast of pentecost.