Leviticus 23:14-16

New Revised Standard Version Catholic Edition

¹⁴ You shall eat no bread or parched grain or fresh ears until that very day, until you have brought the offering of your God: it is a statute forever throughout your generations in all your settlements.

The Festival of Weeks

¹⁵ And from the day after the sabbath, from the day on which you bring the sheaf of the elevation offering, you shall count off seven weeks; they shall be complete. ¹⁶ You shall count until the day after the seventh sabbath, fifty days; then you shall present an offering of new grain to the Lord.