Psalms 42:8

Yet the Lord will command his loving-kindness in the daytime - literally, “By day the Lord will command his mercy;” that is, he will so order or direct his mercy or his favor. The word “daytime” here refers evidently to prosperity; and the expectation of the psalmist was that a time of prosperity would return; that he might hope for better days; that the loving-kindness of God would again be manifested to him. He did not wholly despair. He expected to see better times (compare the notes at Psalms 42:5); and, in view of this, and in the confident assurance of it, he says in the subsequent part of the verse that even in the night - the season of calamity - his song should be unto God, and he would praise Him. Some, however, as DeWette, have understood the words “daytime” and “night” as synonymous with “day and night;” that is, at all times; implying an assurance that God would always show his loving-kindness. But it seems to me that the above is the most correct interpretation.

And in the night his song shall be with me - I will praise him, even in the dark night of calamity and sorrow. God will even then give me such views of himself, and such manifest consolations, that my heart will be full of gratitude, and my lips will utter praise. See the notes at Job 35:10; compare Acts 16:25.

And my prayer unto the God of my life - To God, who has given me life, and who preserves my life. The meaning is, that in the dark night of sorrow and trouble he would not cease to call on God. Feeling that he had given life, and that he was able to sustain and to defend life, he would go to him and supplicate his mercy. He would not allow affliction to drive him from God, but it should lead him the more earnestly and fervently to implore his aid. Afflictions, God’s apparently severe dealings, which it might be supposed would have a tendency to turn people from God, are the very means of leading them to him.