Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary

In prospect of his deliverance the poet promises beforehand to fulfil the duty of thankfulness. עלי, incumbent upon me, as in Pro 7:14; Sa2 18:11. נדריך, with an objective subject, are the vows made to God; and תּודות are distinguished from them, as e.g., in Ch2 29:31. He will suffer neither the pledged שׁלמי נדר nor the שׁלמי תּודה to be wanting; for - so will he be then able to sing and to declare - Thou hast rescued, etc. The perfect after כּי denotes that which is then past, as in Psa 59:17, cf. the dependent passage Psa 116:8. There the expression is ארצות החיּים instead of אור החיּים (here and in Elihu's speech, Job 33:30). Light of life (Joh 8:12) or of the living (lxx τῶν ζώντων) is not exclusively the sun-light of this present life. Life is the opposite of death in the deepest and most comprehensive sense; light of life is therefore the opposite of the night of Hades, of this seclusion from God and from His revelation in human history.