Psalms 51:18

Those who are thoroughly convinced of their misery and danger by sin, would spare no cost to obtain the remission of it. But as they cannot make satisfaction for sin, so God cannot take any satisfaction in them, otherwise than as expressing love and duty to him. The good work wrought in every true penitent, is a broken spirit, a broken and a contrite heart, and sorrow for sin. It is a heart that is tender, and pliable to God's word. Oh that there were such a heart in every one of us! God is graciously pleased to accept this; it is instead of all burnt-offering and sacrifice. The broken heart is acceptable to God only through Jesus Christ; there is no true repentance without faith in him. Men despise that which is broken, but God will not. He will not overlook it, he will not refuse or reject it; though it makes God no satisfaction for the wrong done to him by sin. Those who have been in spiritual troubles, know how to pity and pray for others afflicted in like manner. David was afraid lest his sin should bring judgements upon the city and kingdom. No personal fears or troubles of conscience can make the soul, which has received grace, careless about the interests of the church of God. And let this be the continued joy of all the redeemed, that they have redemption through the blood of Christ, the forgiveness of sins according to the riches of his grace.

Do good in thy good pleasure unto Zion. Let blessings according to thy wont be poured upon thy holy hill and chosen city. Zion was David's favourite spot, whereon he had hoped to erect a temple. The ruling passion is so strong on him, that when he has discharged his conscience he must have a word for Zion. He felt he had hindered the project of honouring the Lord there as he desired, but he prayed God still to let the place of his ark be glorious, and to establish his worship and his worshipping people. Build thou the walls of Jerusalem. This had been one of David's schemes, to wall in the holy city, and he desires to see it completed; but we believe he had a more spiritual meaning, and prayed for the prosperity of the Lord's cause and people. He had done mischief by his sin, and had, as it were, pulled down her walls; he, therefore, implores the Lord to undo the evil, and establish his church. God can make his cause to prosper, and in answer to prayer he will do so. Without his building we labour in vain; therefore are we the more instant and constant in prayer. There is surely no grace in us if we do not feel for the church of God, and take a lasting interest in its welfare.