“Out of the depths have I cried unto Thee, O LORD...Let Israel hope in the Lord: for with the Lord there is mercy, and with Him is plenteous redemption.”- Psalm 130:1,7

When he penned this psalm, the writer, David, was in deep distress, if not of circumstances, yet of conscience. He constantly mentions iniquities and begs forgiveness. He felt like a shipwrecked mariner, carried overboard into the raging sea. Thus, he reviews the situation-“Out of the depths have I cried unto Thee, O Lord.” Yet he lived to tell the tale of deliverance.

Two things the rescued sufferer tells us. First, that, as God delivered him from the power of sin, so He will deliver all His praying, wrestling, believing people. That is the last verse of the psalm-He shall redeem Israel from all his iniquities.” The argument is-He delivered me. What am I more than others? The gracious Lord who saved me will save all those who call upon Him in truth. He delivered me, though laden with iniquities, and His pardoning mercy is unfailing; and therefore, He can and will rescue others from their uttermost distresses. This is a good line of reasoning, for the Lord’s ways are constant, and He will do for all believers what He has done for one of them. The other thing which the Psalmist sets before us is this: we are wise if we apply to God alone for help. He says, “I wait for the Lord, my soul doth wait. My soul waiteth for the Lord more than they that watch for the morning: I say, more than they that watch for the morning.” He incidentally tells us that it is vain to wait upon man, and put our trust in any human support, for the way of deliverance lies alone in reliance upon God, immediately and alone…The psalm encourages us to this by the assurance that the Lord can and will help all that seek Him; and it urges us to let that seeking be distinctly and directly turned to the Most High, to Him alone, and to none other. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2199.cfm