'Citadel' in the Bible

Then King David addressed the entire assembly: "My son Solomon, the one whom God alone has chosen, is still young and inexperienced, and the task is great, since this structure will be a citadel to the LORD God and not for human beings.

Grant to Solomon my son a heart of peace to keep your commands, your statutes, and your regulations to do everything, and to build the citadel for which I have provided."