1 Chronicles 29:27

for forty years. He ruled in Hebron for seven years and in Jerusalem for thirty-three.

2 Samuel 5:4-5

David was thirty years old when he became king. He ruled for forty years.

1 Kings 2:11

He was king of Israel for forty years. He ruled seven years in Hebron and thirty-three years in Jerusalem.

1 Chronicles 3:4

These six were born to David in Hebron, where he reigned seven years and six months. David reigned in Jerusalem thirty-three years,

Treasury of Scripture Knowledge

Summary

And the time that he reigned over Israel was forty years; seven years reigned he in Hebron, and thirty and three years reigned he in Jerusalem.

Bible References

Forty years

1 Chronicles 3:4
These six were born to David in Hebron, where he reigned seven years and six months. David reigned in Jerusalem thirty-three years,
2 Samuel 5:4
David was thirty years old when he became king. He ruled for forty years.
1 Kings 2:11
He was king of Israel for forty years. He ruled seven years in Hebron and thirty-three years in Jerusalem.