1 Chronicles 29:27

And the days which he reigned over Israel were forty years; in Hebron he reigned seven years, and in Jerusalem he reigned thirty and three.

2 Samuel 5:4-5

The son of thirty years was David in his reigning, and he reigned forty years.

1 Kings 2:11

And the days that David reigned over Israel, forty years: in Hebron he reigned seven years, and in Jerusalem he reigned thirty and three years.

1 Chronicles 3:4

Six were born to him in Hebron; and he will reign there seven years and six months: and thirty and three years he reigned in Jerusalem.

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
Six were born to him in Hebron; and he will reign there seven years and six months: and thirty and three years he reigned in Jerusalem.
2 Samuel 5:4
The son of thirty years was David in his reigning, and he reigned forty years.
1 Kings 2:11
And the days that David reigned over Israel, forty years: in Hebron he reigned seven years, and in Jerusalem he reigned thirty and three years.