Song-of-solomon 8:9

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.

8:9 If - This seems to be Christ's answer to the foregoing question of the Jewish church. Christ engages himself to provide for her, as suits best with her condition. If the Gentiles when they are converted shall be like a wall, strong and firm in faith; We, my Father, and I, and the Holy Ghost, as the principal builders, and my ministers as workers with, and under us, will build upon her a palace of silver, will add more strength and beauty to her, will enlarge and adorn her; and if she be as a door, which is weaker than a wall; if she be weak in faith, yet we will not therefore reject her, but we will inclose or (as many others render the word) strengthen or fortify her with boards of cedar, which are not only beautiful, but also strong and durable.