Do good in thy good pleasure unto Zion. It is characteristic of David to pass from prayer for himself to prayer for the people committed to him, and especially to do so at or near the end of a psalm (see Psalms 5:11, Psalms 5:12; Psalms 25:22; Psalms 28:9; Psalms 40:16).
And he closely connects—nay, identifies—the people with their capital city (see Psalms 46:4; Psalms 48:11; Psalms 69:35, etc.). Build thou the walls of Jerusalem. Josephus says that David encompassed the whole city of Jerusalem with walls ('Ant.
Jud.,' 7.3, § 2); and we are told, in the Second Book of Samuel, that he "built round about from Mille and inward." It has been argued that his walls were just approaching their completion at the time of his great sin.