Psalms 18:28

28.For thou shalt light my lamp. In the song in Samuel, the form of the expression is somewhat more precise; for there it is said not that God lights our lamp, but that he himself is our lamp. The meaning, however, comes to the same thing, namely, that it was by the grace of God that David, who had been plunged in darkness, returned to the light. David does not simply give thanks to God for having lighted up a lamp before him, but also for having converted his darkness into light. He, therefore, acknowledges that he had been reduced to such extremity of distress, that he was like a man whose condition was forlorn and hopeless; for he compares the confused and perplexed state of his affairs to darkness. This, indeed, by the transference of material things to things spiritual, may be applied to the spiritual illumination of the understanding; but, at the same time, we must attend to the subject of which David treats, that we may not depart from the true and proper meaning. Now, as he acknowledges that he had been restored to prosperity by the favor of God, which was to him, as it were, a life-giving light, let us, after his example, regard it as certain that we will never have the comfort of seeing our adversities brought to an end, unless God disperse the darkness which envelops us, and restore to us the light of joy. Let it not, however, be distressing to us to walk through darkness, provided God is pleased to perform to us the office of a lamp. In the following verse, David ascribes his victories to God, declaring that, under his conduct, he had broken through the wedges or phalanxes of his enemies, and had taken by storm their fortified cities. (425) Thus we see that, although he was a valiant warrior, and skilled in arms, he arrogates nothing to himself. As to the tenses of the verbs, we would inform our readers once for all, that in this psalm David uses the past and the future tenses indifferently, not only because he comprehends different histories, but also because he presents to himself the things of which he speaks as if they were still taking place before his eyes, and, at the same time, describes a continued course of the grace of God towards him.