Exodus 34:22
And you shall observe the feast of weeks, of the first fruits of wheat harvest, and the feast of ingathering at the year's end.
Nave's Topical Index—AKJV

Leviticus 23:15-17
And you shall count to you from the morrow after the sabbath, from the day that you brought the sheaf of the wave offering; seven sabbaths shall be complete:
Nave's Topical Index—AKJV