In 2 Samuel 2:11, David's reign in Hebron is given as 7.5 years, the first part of his total 40-year reign.

In 1 Chronicles 29:27, the same 40-year reign is given with the breakdown: 7 in Hebron, 33 in Jerusalem.

In 1 Kings 2:11, the same 40-year reign is restated with the breakdown (7 in Hebron, 33 in Jerusalem).

In 1 Chronicles 3:4, the reign is broken into 7.5 years in Hebron and 33 in Jerusalem, matching the total.

In 1 Kings 1:1, David is old and frail at the end of his 40-year reign, showing the conclusion of his rule.

In 1 Chronicles 26:31, a census in David's fortieth year confirms the 40-year reign by placing an event in that year.

In Luke 3:23, Jesus also began his ministry at about age 30, mirroring David's start as king.

In Genesis 41:46, Joseph was also 30 when he began serving Pharaoh, paralleling David's age at becoming king.