Song of Solomon 8:9

Verse 9. If she be a wall] All these expressions, says Calmet, show that it was necessary to provide a husband for this young sister. For a woman without a husband is like a wall without towers, and without defense; is like a gate or door without bar or lock; and like a city without walls. They must therefore provide for their sister a rich, powerful, and illustrious man; qualities here figured by towers or palaces of silver, and doors of cedar. As it is customary to build towers upon a wall, and to put bolts and bars upon a door in order to secure it, so the expressions may point out the defense, protection, and guardianship which they imagined this young woman to require.