Acts 2:1

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

Acts 20:16

For Paul had determined to sail by Ephesus, that he might not spend any time in Asia; for he hasted, if it were possible, to be at Jerusalem on the day of Pentecost.

1 Corinthians 16:8

But I will stay at Ephesus till Pentecost.

Acts 1:13-15

And when they were come in, they went up into the upper-room, where both Peter and James, and John and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alpheus, and Simon Zelotes, and Jude the brother of James tarried.

Acts 2:46

And continuing daily with one accord in the temple, and breaking the bread at home, they ate their meat with gladness and singleness of heart,

Acts 4:24

And when they heard it, they lifted up their voice to God with one accord, and said, Lord, thou art the God who madest heaven and earth, and the sea, and all that in them is:

Acts 4:32

And the multitude of them that believed were of one heart, and of one soul: and not so much as one said that ought of the things which he had, was his own, but they had all things common.

Acts 5:12

And many signs and wonders were wrought among the people by the hands of the apostles: (and they were all with one accord in Solomon's portico:

Romans 15:6

That ye may with one mind and one mouth glorify the God and Father of our Lord Jesus Christ.

Philippians 1:27

Only let your behaviour be worthy the gospel of Christ, that whether I come and see you, or be absent, I may hear concerning you, that ye stand fast, in one spirit, with one soul striving together for the faith of the gospel,

Philippians 2:2

that ye think the same thing, having the same love, being of one soul, of one mind.

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 determined to sail by Ephesus, that he might not spend any time in Asia; for he hasted, if it were possible, to be at Jerusalem on the day of Pentecost.
1 Corinthians 16:8
But I will stay at Ephesus till Pentecost.

They

Acts 2:46
And continuing daily with one accord in the temple, and breaking the bread at home, they ate their meat with gladness and singleness of heart,
Acts 1:13
And when they were come in, they went up into the upper-room, where both Peter and James, and John and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alpheus, and Simon Zelotes, and Jude the brother of James tarried.
Acts 4:24
And when they heard it, they lifted up their voice to God with one accord, and said, Lord, thou art the God who madest heaven and earth, and the sea, and all that in them is:
Acts 5:12
And many signs and wonders were wrought among the people by the hands of the apostles: (and they were all with one accord in Solomon's portico:
Romans 15:6
That ye may with one mind and one mouth glorify the God and Father of our Lord Jesus Christ.
Philippians 1:27
Only let your behaviour be worthy the gospel of Christ, that whether I come and see you, or be absent, I may hear concerning you, that ye stand fast, in one spirit, with one soul striving together for the faith of the gospel,
Philippians 2:2
that ye think the same thing, having the same love, being of one soul, of one mind.

General references

Hebrews 13:1
Let brotherly love continue.