David's first thought after ascending the throne was to wrest Jerusalem, sacred since the days of Adam, Noah, and Abraham, from the grasp of the heathen. The plan was not easy of execution for various reasons. The Jebusites, the possessors of Jerusalem, were the posterity of those sons of Heth who had ceded the Cave of Machpelah to Abraham only on condition that their descendants should never be forcibly dispossessed of their capital city Jerusalem.
In perpetuation of this agreement between Abraham and the sons of Heth, monuments of brass were erected, and when David approached Jerusalem with hostile intent, the Jebusites pointed to Abraham's promise engraven upon them and still plainly to be read. They maintained that before David could take the city, which they had surrounded with a high wall, he would have to destroy the monuments. Joab devised a plan of getting into Jerusalem.
He set up a tall cypress tree near the wall, bent it downward, and standing on David's head, he grasped the very tip of the tree. When the tree rebounded, Joab sat high above the wall, and could jump down upon it. Once in the city, he destroyed the monuments, and possessed himself of Jerusalem. For David a miracle had happened; the wall had lowered itself before him so that he could walk into the city without difficulty.
David, however, was not desirous of using forcible means. He therefore offered the Jebusites six hundred shekels, fifty shekels for each Israelitish tribe. The Jebusites accepted the money, and gave David a bill of sale.