Acts 2:1

At length, on the day of the Harvest Festival, they had all met in one place;

Acts 20:16

For Paul's plan was to sail past Ephesus, so as not to spend much time in the province of Asia; since he was very desirous of being in Jerusalem, if possible, on the day of the Harvest Festival.

1 Corinthians 16:8

I shall remain in Ephesus, however, until the time of the Harvest Festival,

Acts 1:13-15

They entered the city, and they went up to the upper room which was now their fixed place for meeting. Their names were Peter and John, James and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, Simon the Zealot, and Judas the brother of James.

Acts 2:46

And, day by day, attending constantly in the Temple with one accord, and breaking bread in private houses, they took their meals with great happiness and single-heartedness,

Acts 4:24

And they, upon hearing the story, all lifted up their voices to God and said, "O Sovereign Lord, it is Thou who didst make Heaven and earth and sea, and all that is in them,

Acts 4:32

Among all those who had embraced the faith there was but one heart and soul, so that none of them claimed any of his possessions as his own, but everything they had was common property;

Acts 5:12

Many signs and marvels continued to be done among the people by the Apostles; and by common consent they all met in Solomon's Portico.

Romans 15:6

so that with oneness both of heart and voice you may glorify the God and Father of our Lord Jesus Christ.

Philippians 1:27

Only let the lives you live be worthy of the Good News of the Christ, in order that, whether I come and see you or, being absent, only hear of you, I may know that you are standing fast in one spirit and with one mind, fighting shoulder to shoulder for the faith of the Good News.

Philippians 2:2

united by mutual love, with harmony of feeling giving your minds to one and the same object.

Treasury of Scripture Knowledge

Summary

And when the day of Pentecost was fully come, they were all with one accord in one place.

General references

Bible References

The day

Acts 20:16
For Paul's plan was to sail past Ephesus, so as not to spend much time in the province of Asia; since he was very desirous of being in Jerusalem, if possible, on the day of the Harvest Festival.
1 Corinthians 16:8
I shall remain in Ephesus, however, until the time of the Harvest Festival,

They

Acts 2:46
And, day by day, attending constantly in the Temple with one accord, and breaking bread in private houses, they took their meals with great happiness and single-heartedness,
Acts 1:13
They entered the city, and they went up to the upper room which was now their fixed place for meeting. Their names were Peter and John, James and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, Simon the Zealot, and Judas the brother of James.
Acts 4:24
And they, upon hearing the story, all lifted up their voices to God and said, "O Sovereign Lord, it is Thou who didst make Heaven and earth and sea, and all that is in them,
Acts 5:12
Many signs and marvels continued to be done among the people by the Apostles; and by common consent they all met in Solomon's Portico.
Romans 15:6
so that with oneness both of heart and voice you may glorify the God and Father of our Lord Jesus Christ.
Philippians 1:27
Only let the lives you live be worthy of the Good News of the Christ, in order that, whether I come and see you or, being absent, only hear of you, I may know that you are standing fast in one spirit and with one mind, fighting shoulder to shoulder for the faith of the Good News.
Philippians 2:2
united by mutual love, with harmony of feeling giving your minds to one and the same object.

General references

Hebrews 13:1
Let brotherly love always continue.