Do good in your good pleasure unto Zion: build you the walls of Jerusalem.
Read Chapter 51
Augustine of Hippo
"Deal kindly, O Lord, in Thy good will with Sion" (ver. 18). With this Sion deal kindly. What is Sion? A city holy. What is a city holy? That which cannot be hidden, being upon a mountain established. Sion in prospect, because it hath prospect of something which it hopeth for. For Sion is interpreted "prospect," and Jerusalem, "vision of peace." Ye perceive then yourselves to be in Sion and in Jerusalem, if being sure ye look for hope that is to be, and if ye have peace with God. "And be the walls of Jerusalem builded." "Deal kindly, O Lord, in Thy good will with Sion, and be the walls of Jerusalem builded." For not to herself let Sion ascribe her merits: do Thou with her deal kindly, "Be the walls of Jerusalem builded:" be the battlements of our immortality laid, in faith and hope and charity.
Deal. These two verses have no necessary connexion with the preceding: they may have been added by some prophet at Babylon, (Calmet) or David foresaw the destruction of the city by the Chaldeans. (St. Chrysostom)
He might fear that his sin would draw ruin on the capital, as a much less offence did, and as in all ages, the sins of the rulers have fallen on their subjects, 2 Kings xxiv. (Haydock)
Though the place was not destitute of fortifications, (Calmet) he might pray that they might be completed, (Berthier) as they were by Solomon, who built the temple and various walls, so that David might very will add this conclusion, (3 Kings iii. 1., and ix. 15.; Haydock) alluding to the sacrifices which should be offered in the future temple. (Berthier)
He insinuates, that his pardon may prove beneficial to his people, and sues for it to be granted for their sakes. (Menochius)