Exodus 34:22

Thou shalt observe the feast of weeks with the first fruits of wheat harvest, and the feast of ingathering at the years' end.

Exodus 23:16

And the feast of Harvest, when thou reapest the first fruits of thy labors which thou hast sown in the field. And the feast of ingathering, in the end of the year: when thou hast gathered in thy labors out of the field.

Numbers 28:16-31

And the fourteenth day of the first month shall be Passover unto the LORD.

Numbers 29:12-39

And the fifteenth day of the seventh month shall be a holy day and ye shall do no laborious work therein, and ye shall keep a feast unto the LORD of seven days long.

Deuteronomy 16:10-15

and keep the feast of weeks unto the LORD thy God, that thou give a freewill offering of thine hand unto the LORD thy God according as the LORD thy God hath blessed thee.

John 7:2

The Jews' tabernacle feast was at hand.

Acts 2:1

When the fiftieth day was come, they were all with one accord gathered together in one place.

Treasury of Scripture Knowledge

Summary

And thou shalt observe the feast of weeks, of the firstfruits of wheat harvest, and the feast of ingathering at the year's end.

Bible References

Feast of weeks

Exodus 23:16
And the feast of Harvest, when thou reapest the first fruits of thy labors which thou hast sown in the field. And the feast of ingathering, in the end of the year: when thou hast gathered in thy labors out of the field.
Numbers 28:16
And the fourteenth day of the first month shall be Passover unto the LORD.
Numbers 29:12
And the fifteenth day of the seventh month shall be a holy day and ye shall do no laborious work therein, and ye shall keep a feast unto the LORD of seven days long.
Deuteronomy 16:10
and keep the feast of weeks unto the LORD thy God, that thou give a freewill offering of thine hand unto the LORD thy God according as the LORD thy God hath blessed thee.
John 7:2
The Jews' tabernacle feast was at hand.
Acts 2:1
When the fiftieth day was come, they were all with one accord gathered together in one place.

General references

Exodus 23:14
"Three feasts thou shalt hold unto me in a year.
Leviticus 23:15
"'And ye shall count from the morrow after the Sabbath: even from the day that ye brought the sheaf of the wave offering, seven weeks complete:
Deuteronomy 16:9
Then reckon the seven weeks, and begin to reckon the seven weeks when the sickle beginneth in the corn,