My soul is also sore vexed - The word “soul” here is used in the sense in which it is commonly with us, as denoting the mind. The idea is, that his sorrows were not merely those of the bodily frame. They had a deeper seat than even the bones. His mind, his soul, was full of anguish also, in view of the circumstances which surrounded him, and which had brought on these bodily afflictions.
But thou, O Lord - This is a broken sentence, as if he had commenced an address to God, but did not complete it. It is as if he had said, “Here I suffer and languish; my sorrows are deep and unmitigated; as for thee, O Lord” - as if he were about to say that he had hoped God would interpose; or, that his dealings were mysterious; or, that they seemed strange or severe; but he ends the sentence by no language of complaint or complaining, but by simply asking “how long” these sorrows were to continue.
How long? - That is, how long wilt thou leave me thus to suffer? How long shall my unmitigated anguish continue? How long will it be ere thou wilt interpose to relieve me? The language implies that in his apprehension it was already a long time - as time usually seems long to a sufferer (compare Job 7:2-4), and that he was constantly looking out for God to interpose and help him. This is language such as all persons may be inclined to use on beds of pain and languishing. It seems indeed long to them now; it will, however, seem short when they look back upon it from the glories of the heavenly world. Compare 2 Corinthians 4:17-18.