Leviticus 23:15
"Starting the day after the Sabbath, count for yourselves seven weeks from the day you brought the sheaf of the wave offering. They are to be complete.
Exodus 34:22
"You are to observe the Festival of Weeks, the first fruits of the wheat harvest, and the Festival of Tabernacles at the turn of the year.
Leviticus 23:10-11
"Tell the Israelis that when you enter the land that I'm about to give you and gather its produce, you are to bring a sheaf from the first portion of your harvest to the priest,
Leviticus 25:8
"Count for yourselves seven years of Sabbaths seven times seven years. This set of seven weeks of years total 49 years for you.
Deuteronomy 16:9-10
"Count off seven weeks from when the sickle is first put to standing grain.
Numbers 28:26
"On the first day of your harvest season, you are to hold a sacred assembly when you present your first fruits during the Festival of Weeks. No servile work is to be done.