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

Luke 3:23
Jesus Himself was about thirty years old when He began His ministry. He was regarded as the son of Joseph, the son of Heli,

Genesis 41:46
Now Joseph was thirty years old when he entered the service of Pharaoh king of Egypt. And Joseph left Pharaoh's presence and traveled throughout the land of Egypt.

Numbers 4:3
men from thirty to fifty years old--everyone who is qualified to serve in the work at the Tent of Meeting.

1 Kings 2:11
The length of David's reign over Israel was forty years--seven years in Hebron and thirty-three years in Jerusalem.

1 Chronicles 3:4
These six sons were born to David in Hebron, where he reigned seven years and six months. And David reigned in Jerusalem thirty-three years,

1 Chronicles 26:31
As for the Hebronites, Jerijah was the chief of the Hebronites, according to the genealogies of his ancestors. In the fortieth year of David's reign the records were searched, and strong, capable men were found among the Hebronites at Jazer in Gilead.

1 Chronicles 29:27
The length of David's reign over Israel was forty years--seven years in Hebron and thirty-three years in Jerusalem.

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