isaiah 38:17 Behold, for peace I had great bitterness: but thou hast in love to my soul delivered it from the pit of corruption: for thou hast cast all my sins behind thy back. - Free Bible Online

      17. for peace--instead of the prosperity which I had previously.
      great bitterness--literally, "bitterness to me, bitterness"; expressing intense emotion.
      in love--literally, "attachment," such as joins one to another tenderly; "Thou hast been lovingly attached to me from the pit"; pregnant phrase for, Thy love has gone down to the pit, and drawn me out from it. The "pit" is here simply death, in Hezekiah's sense; realized in its fulness only in reference to the soul's redemption from hell by JesusChrist (Isa 61:1), who went down to the pit for that purpose Himself (Ps 88:4-6; Zec 9:11, 12; Heb 13:20). "Sin" and sickness are connected (Ps 103:3; compare Isa 53:4, with Mt 8:17; 9:5, 6), especially under the Old Testament dispensation of temporal sanctions; but even now, sickness, though not invariably arising from sin in individuals, is connected with it in the general moral view.
      cast . . . behind back--consigned my sins to oblivion. The same phrase occurs (1Ki 14:9; Ne 9:26; Ps 50:17). Contrast Ps 90:8, "Thou hast set our iniquities before thee, our secret sins in the light of thy countenance."

JFB.