2 Samuel 5:4

5:4 David was thirty years old when he began to reign and he reigned for forty years.

2 Samuel 15:7

15:7 After four years Absalom said to the king, “Let me go and repay my vow that I made to the Lord while I was in Hebron.

2 Samuel 2:10

2:10 Ish-bosheth son of Saul was forty years old when he began to rule over Israel. He ruled two years. However, the people of Judah followed David.

2 Samuel 10:18

10:18 The Arameans fled before Israel. David killed 700 Aramean charioteers and 40,000 foot soldiers. He also struck down Shobach, the general in command of the army, who died there.