Exodus 34:22
"And thou shalt observe the feast of weeks, of the firstfruits of wheat harvest, and the feast of ingathering at the year’s end."
Cross References (ranked by relevance)
Exodus 23:16
And the feast of harvest, the firstfruits of thy labours, which thou hast sown in the field: and the feast of ingathering, which is in the end of the year, when thou hast gathered in thy labours out of the field.
John 7:2
Now the Jews’ feast of tabernacles was at hand.
Acts 2:1
And when the day of Pentecost was fully come, they were all with one accord in one place.