'Seven' in the Bible

The length of time that David was king in Hebron over the house of Judah was seven years and six months.

In Hebron he reigned over Judah seven years and six months, and in Jerusalem he reigned 33 years over all Israel and Judah.

let seven of his male descendants be handed over to us so we may hang them in the presence of the Lord at Gibeah of Saul, the Lord’s chosen.”The king answered, “I will hand them over.”

and handed them over to the Gibeonites. They hanged them on the hill in the presence of the Lord; the seven of them died together. They were executed in the first days of the harvest at the beginning of the barley harvest.