Acts 2:1

On the day of the Harvest Festival, they were all meeting together,

Acts 20:16

For Paul had decided to sail past Ephesus, so that he would not have to lose any time in Asia, for he was hurrying to reach Jerusalem, if possible, by the day of the Harvest Festival.

1 Corinthians 16:8

But I shall stay in Ephesus until the Harvest Festival,

Acts 1:13-15

When they entered the city they went to the upstairs room where they were staying. There were Peter, John, James and Andrew, Philip and Thomas, Bartholomew and Matthew, James, the son of Alpheus, Simon the Zealot, and Judas, the son of James.

Acts 2:46

Day after day they all went regularly to the Temple, they broke their bread together in their homes, and they ate their food with glad and simple hearts,

Acts 4:24

When they heard it, with one impulse they all raised their voices to God and said, "Master, it was you who made heaven, earth, and sea, and everything that is in them,

Acts 4:32

There was but one heart and soul in the multitude who had become believers, and not one of them claimed anything that belonged to him as his own, but they shared everything they had with one another.

Acts 5:12

They would all meet together in Solomon's Colonnade.

Romans 15:6

that you may praise the God and Father of our Lord Jesus Christ with one accord and one voice.

Philippians 1:27

Whatever happens, show yourselves citizens worthy of the good news of the Christ, so that whether I come and see you or am kept away and only hear news of you, I may know that you are standing firm with one spirit, one purpose, fighting side by side for faith in the good news.

Philippians 2:2

make me perfectly happy by living in harmony, with the same attitude of love, with the same feeling and purpose.

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 had decided to sail past Ephesus, so that he would not have to lose any time in Asia, for he was hurrying to reach Jerusalem, if possible, by the day of the Harvest Festival.
1 Corinthians 16:8
But I shall stay in Ephesus until the Harvest Festival,

They

Acts 2:46
Day after day they all went regularly to the Temple, they broke their bread together in their homes, and they ate their food with glad and simple hearts,
Acts 1:13
When they entered the city they went to the upstairs room where they were staying. There were Peter, John, James and Andrew, Philip and Thomas, Bartholomew and Matthew, James, the son of Alpheus, Simon the Zealot, and Judas, the son of James.
Acts 4:24
When they heard it, with one impulse they all raised their voices to God and said, "Master, it was you who made heaven, earth, and sea, and everything that is in them,
Acts 5:12
They would all meet together in Solomon's Colonnade.
Romans 15:6
that you may praise the God and Father of our Lord Jesus Christ with one accord and one voice.
Philippians 1:27
Whatever happens, show yourselves citizens worthy of the good news of the Christ, so that whether I come and see you or am kept away and only hear news of you, I may know that you are standing firm with one spirit, one purpose, fighting side by side for faith in the good news.
Philippians 2:2
make me perfectly happy by living in harmony, with the same attitude of love, with the same feeling and purpose.

General references

Hebrews 13:1
Your love for the brotherhood must continue.