I went down to the bottoms of the mountains; the earth with her bars was about me for ever: yet hast thou brought up my life from corruption, O LORD my God.
I went down to the bottoms of the mountains - their extremities, where they terminate in the hidden depths of the sea. Compare Psalms 18:7, "the foundations of the hills;" Psalms 18:15, "the foundations of the world."
The earth with her bars was about me - the earth, the land of the living, was shut against me. The bars are the long submarine rocks, which were, as it were, his prison bars.
Forever - so far as any effort of mine can deliver me.
Yet hast thou brought up my life from corruption. As in the previous clauses he expresses the hopelessness of his state, so in this, his sure hope of deliverance through Yahweh's infinite resources. 'Against hope he believes in hope,' and speaks as if the deliverance were actually already accomplished. Hezekiah seems to have incorporated Jonah's very words in his prayer, just as Jonah appropriated the language of the Psalms (Isaiah 38:17, "Thou hast in love to my soul delivered it from the pit of corruption: for thou hast cast all my sins behind thy back").