Acts 2:1

In the course of the Festival at the close of the Harvest the disciples had all met together,

Acts 20:16

For Paul had decided to sail past Ephesus, so as to avoid spending much time in Roman Asia. He was making haste to reach Jerusalem, if possible, by the Festival at the close of the Harvest.

1 Corinthians 16:8

I intend, however, staying at Ephesus till the Festival at the close of the Harvest;

Acts 1:13-15

When they reached Jerusalem, they went to the upstairs room, where they were staying. There were there Peter, John, James, and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, Simon the Zealot, and Judas the son of James.

Acts 2:46

Every day they devoted themselves to meeting together in the Temple Courts, and to the Breaking of Bread at their homes, while they partook of their food in simple-hearted gladness, praising God, and winning the good-will of all the people.

Acts 4:24

All who heard their story, moved by a common impulse, raised their voices to God in prayer: "O Sovereign Lord, it is you who has 'made the heavens, the earth, the sea, and everything that is in them,'

Acts 4:32

The whole body of those who had become believers in Christ were of one heart and mind. Not one of them claimed any of his goods as his own, but everything was held for the common use.

Acts 5:12

Many signs and wonders continued to occur among the people, through the instrumentality of the Apostles, whose custom it was to meet all together in the Colonnade of Solomon;

Romans 15:6

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

Philippians 1:27

Under all circumstances let your lives be worthy of the Good News of the Christ: so that, whether I come and see you, or whether I hear of your affairs at a distance, I may know that you are standing firm, animated by one spirit, and joining with one heart in a common struggle for the Faith taught by the Good News,

Philippians 2:2

I entreat you to make my happiness complete--Live together animated by the same spirit and in mutual love, one in heart, animated by one Spirit.

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 as to avoid spending much time in Roman Asia. He was making haste to reach Jerusalem, if possible, by the Festival at the close of the Harvest.
1 Corinthians 16:8
I intend, however, staying at Ephesus till the Festival at the close of the Harvest;

They

Acts 2:46
Every day they devoted themselves to meeting together in the Temple Courts, and to the Breaking of Bread at their homes, while they partook of their food in simple-hearted gladness, praising God, and winning the good-will of all the people.
Acts 1:13
When they reached Jerusalem, they went to the upstairs room, where they were staying. There were there Peter, John, James, and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, Simon the Zealot, and Judas the son of James.
Acts 4:24
All who heard their story, moved by a common impulse, raised their voices to God in prayer: "O Sovereign Lord, it is you who has 'made the heavens, the earth, the sea, and everything that is in them,'
Acts 5:12
Many signs and wonders continued to occur among the people, through the instrumentality of the Apostles, whose custom it was to meet all together in the Colonnade of Solomon;
Romans 15:6
So that with one heart and one voice you may praise the God and Father of Jesus Christ, our Lord.
Philippians 1:27
Under all circumstances let your lives be worthy of the Good News of the Christ: so that, whether I come and see you, or whether I hear of your affairs at a distance, I may know that you are standing firm, animated by one spirit, and joining with one heart in a common struggle for the Faith taught by the Good News,
Philippians 2:2
I entreat you to make my happiness complete--Live together animated by the same spirit and in mutual love, one in heart, animated by one Spirit.

General references

Hebrews 13:1
Let your love for the Brethren continue. :24 Give our greeting to all your Leaders, and to all Christ's People. Our friends from Italy send their greetings to you.