And thou, O Jehovah, how long? This elliptical form of expression serves to express more strongly the vehemence of grief, which not only holds the minds of men bound up, but likewise their tongues, breaking and cutting short their speech in the middle of the sentence. The meaning, however, in this abrupt expression is doubtful. Some, to complete the sentence, supply the words, Wilt thou afflict me, or continue to chasten me? Others read, How long wilt thou delay thy mercy? But what is stated in the next verse shows that this second sense is the more probable, for he there prays to the Lord to look upon him with an eye of favor and compassion. He, therefore, complains that God has now forsaken him, or has no regard to him, just as God seems to be far of from us whenever his assistance or grace does not actually manifest itself in our behalf. God, in his compassion towards us, permits us to pray to him to make haste to succor us; but when we have freely complained of his long delay, that our prayers or sorrow, on this account, may not pass beyond bounds we must submit our case entirely to his will, and not wish him to make greater haste than shall seem good to him.

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.

How long? - How long shall I continue under this malady? How long will it be before thou speak peace to my troubled heart?

(c) My soul is also sore vexed: but thou, O LORD, how long?
(c) His conscience is also touched with the fear of God's judgment.

My soul is also sore vexed,.... Or "exceedingly troubled" (c), and even frightened and thrown into a consternation with indwelling sin, and on account of actual transgressions, and by reason of the hidings of God's face, and through the temptations of Satan, and because of the fear of death; to which Old Testament saints were very incident.
But thou, O Lord, how long? it is an abrupt expression, the whole he designed is not spoken, being hindered through the grief and sorrow with which his heart was overwhelmed; and is to be supplied after this manner,
"shall I have refreshment?''
as the Chaldee paraphrase; or,
"wilt thou look and not heal me?''
as Jarchi; or
"my soul be troubled?''
as Aben Ezra; or
"shall I be afflicted, and thou wilt not heal me?''
as Kimchi; or
"wilt thou afflict me, and not arise to my help?''
see Psalm 13:1.
(c) "turbata est valde", V. L. "conturbata", Junius & Tremellius, Piscator; "territa valde": Pagninus, Montanus; "consternata valde", Cocceius.

how long?--shall this be so (compare Psalm 79:5).
but--or, "and."
thou--The sentence is incomplete as expressive of strong emotion.