Thou art Gilead unto me, and the head of Lebanon - Perhaps in allusion, says Dahler, to the oaks of Gilead, and the cedars of Mount Lebanon, of which the palace was constructed. Lebanon was the highest mountain in Israel, and Gilead the richest and most fertile part of the country; and were, therefore, proper emblems of the reigning family. Though thou art the richest and most powerful, I, who raised thee up, can bring thee down and make thee a wilderness.
Omit and. “Thou art a Gilead unto me, a summit of Lebanon.”
Yet surely - literally, if not, the form of an oath with the imprecation omitted. For the full form see Numbers 14:23.
A wilderness, and cities - Omit and. The meaning is: If the house of David does not hear God‘s words, though it be now grand as Lebanon, God will make it a wilderness, even uninhabited cities; the house of David being regarded as equivalent to the kingdom of Judah.