Adam Clarke on Psalms 9:13

Have mercy upon me, O Lord - David, having laid down the preceding maxims, now claims his part in their truth. I also am in trouble through the unjust dealings of my enemies; I am brought to the gates of death; have mercy on me, and lift me up, that, being saved from the gates of death, I may show forth thy praise in the gates of the daughter of Zion. The gates of death - an open grave, leading to a yawning hell. The gates of the daughter of Zion - all the ordinances of God, by which the soul is helped forward to heaven.