1 Chronicles 29:27

And the space he reigned over Israel was forty years: seven years in Hebron and thirty three years in Jerusalem.

2 Samuel 5:4-5

David was thirty years old when he began to reign, and he reigned forty years.

1 Kings 2:11

And the days which David reigned upon Israel were forty years: seven years in Hebron, and thirty and three years in Jerusalem.

1 Chronicles 3:4

These six were born him in Hebron where he reigned seven years and six months. And in Jerusalem he reigned 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 him in Hebron where he reigned seven years and six months. And in Jerusalem he reigned thirty three years.
2 Samuel 5:4
David was thirty years old when he began to reign, and he reigned forty years.
1 Kings 2:11
And the days which David reigned upon Israel were forty years: seven years in Hebron, and thirty and three years in Jerusalem.