Exodus 23:16

23:16 “You are also to observe the Feast of Harvest, the firstfruits of your labors that you have sown in the field, and the Feast of Ingathering at the end of the year when you have gathered in your harvest out of the field.

Leviticus 23:15-21

The Festival of Weeks

23:15 “‘You must count for yourselves seven weeks from the day after the Sabbath, from the day you bring the wave offering sheaf; they must be complete weeks. 23:16 You must count fifty days – until the day after the seventh Sabbath – and then you must present a new grain offering to the Lord. 23:17 From the places where you live you must bring two loaves of bread for a wave offering; they must be made from two tenths of an ephah of fine wheat flour, baked with yeast, as first fruits to the Lord. 23:18 Along with the loaves of bread, you must also present seven flawless yearling lambs, one young bull, and two rams. They are to be a burnt offering to the Lord along with their grain offering and drink offerings, a gift of a soothing aroma to the Lord. 23:19 You must also offer one male goat for a sin offering and two yearling lambs for a peace offering sacrifice, 23:20 and the priest is to wave them – the two lambs – along with the bread of the first fruits, as a wave offering before the Lord; they will be holy to the Lord for the priest.

23:21 “‘On this very day you must proclaim an assembly; it is to be a holy assembly for you. You must not do any regular work. This is a perpetual statute in all the places where you live throughout your generations.

Acts 2:1

The Holy Spirit and the Day of Pentecost

2:1 Now when the day of Pentecost had come, they were all together in one place.