2 Samuel 5:4

David was thirty years old when he became king, and he reigned forty years.

1 Chronicles 26:31

Of the Hebronites: Jerijah was the chief (these Hebronites were examined according to their descendants and fathers’ households in the fortieth [and final] year of David’s reign, and men of courage and ability were found among them at Jazer in Gilead)

1 Chronicles 29:27

The time that he reigned over Israel was forty years; he reigned seven years in Hebron and thirty-three years in Jerusalem.

Luke 3:23

When He began His ministry, Jesus Himself was about thirty years of age, being, as was supposed, the son of Joseph, the son [by marriage] of Eli,

1 Kings 2:11

The time that David reigned over Israel was forty years: he reigned seven years in Hebron and thirty-three years in Jerusalem.

1 Chronicles 3:4

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

Treasury of Scripture Knowledge

Summary

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

Thirty

Bible References

Thirty

Luke 3:23
When He began His ministry, Jesus Himself was about thirty years of age, being, as was supposed, the son of Joseph, the son [by marriage] of Eli,

Forty

1 Chronicles 26:31
Of the Hebronites: Jerijah was the chief (these Hebronites were examined according to their descendants and fathers’ households in the fortieth [and final] year of David’s reign, and men of courage and ability were found among them at Jazer in Gilead)
1 Chronicles 29:27
The time that he reigned over Israel was forty years; he reigned seven years in Hebron and thirty-three years in Jerusalem.