Deuteronomy 16:8-10 Revised Standard Version Catholic Edition (RSVCE)
8 For six days you shall eat unleavened bread; and on the seventh day there shall be a solemn assembly to the Lord your God; you shall do no work on it.
The Festival of Weeks Reviewed
9 “You shall count seven weeks; begin to count the seven weeks from the time you first put the sickle to the standing grain. 10 Then you shall keep the feast of weeks to the Lord your God with the tribute of a freewill offering from your hand, which you shall give as the Lord your God blesses you;