Have mercy upon me. As he earnestly calls upon God to be merciful to him, it is from this the more clearly manifest, that by the terms anger and indignation he did not mean cruelty or undue severity, but only such judgment as God executes upon the reprobate, whom he does not spare in mercy as he does his own children. If he had complained of being unjustly and too severely punished, he would now have only added something to this effect: Restrain thyself, that in punishing me thou mayest not exceed the measure of my offense. In betaking himself, therefore, to the mercy of God alone, he shows that he desires nothing else than not to be dealt with according to strict justice, or as he deserved. In order to induce God to exercise his forgiving mercy towards him, he declares that he is ready to fail: Have mercy upon me, O Jehovah, for I am weak As I have said before, he calls himself weak, not because he was sick, but because he was cast down and broken by what had now befallen him. And as we know that the design of God in inflicting punishment upon us, is to humble us; so, whenever we are subdued under his rod, the gate is opened for his mercy to come to us. Besides, since it is his peculiar office to heal the diseased to raise up the fallen, to support the weak, and, finally, to give life to the dead; this, of itself, is a sufficient reason why we should seek his favor, that we are sinking under our afflictions. After David has protested that he placed his hope of salvation in the mercy of God alone, and has sorrowfully set forth how much he is abased, he subjoins the effect which this had in impairing his bodily health, and prays for the restoration of this blessing: Heal me, O Jehovah And this is the order which we must observe, that we may know that all the blessings which we ask from God flow from the fountain of his free goodness, and that we are then, and then only, delivered from calamities and chastisements, when he has had mercy upon us. -- For my bones are afraid This confirms what I have just now observed, namely, that, from the very grievousness of his afflictions, he entertained the hope of some relief; for God, the more he sees the wretched oppressed and almost overwhelmed, is just so much the more ready to succor them. He attributes fear to his bones, not because they are endued with feeling, but because the vehemence of his grief was such that it affected his whole body. He does not speak of his flesh, which is the more tender and susceptible part of the corporeal system, but he mentions his bones, thereby intimating that the strongest parts of his frame were made to tremble for fear. He next assigns the cause of this by saying, And my soul is greatly afraid. The connective particle and, in my judgment, has here the meaning of the causal particle for, as if he had said, so severe and violent is the inward anguish of my heart, that it affects and impairs the strength of every part of my body. I do not approve of the opinion which here takes soul for life, nor does it suit the scope of the passage.

Have mercy upon me, O Lord - That is, be gracious to me; or, show me compassion. This language may be used either in view of sin, of suffering, or of danger. It is a cry to God to interpose, and remove some present source of trouble, and may be employed by one who feels that he is a sinner, or by one on a bed of pain, or by one surrounded by enemies, or by one at the point of death, or by one who is looking out with apprehension upon the eternal world. It is commonly, indeed (compare Psalm 51:1), a cry to God in view of sin, pleading for pardon and salvation; but here it is a cry in view of trouble and danger, outward sorrow and mental anguish, that had overcome the strength of the sufferer and laid him on a bed of languishing. See introduction to the psalm, Section 3.
For I am weak - The original word here, אמלל 'ûmlal, means properly to languish or droop, as plants do that are blighted, Isaiah 24:7, or as fields do in a drought, Isaiah 16:8, and is here applied to a sick person whose strength is withered and gone. The condition of such an one is beautifully compared with a plant that withers for lack of moisture; and the word is used in this sense here, as referring to the psalmist himself when sick, as the result of his outward and mental sorrows. Such an effect has not been uncommon in the world. There have been numberless cases where sorrow has prostrated the strength - as a plant withers - and has brought on languishing sickness.
O Lord, heal me - This is language which would be properly applied to a case of sickness, and therefore, it is most natural to interpret it in this sense in this place. Compare Isaiah 19:22; Isaiah 30:26; Job 5:18; Genesis 20:17; Psalm 60:2; 2-Chronicles 16:12; Deuteronomy 28:27.
For my bones are vexed - The word "vexed" we now commonly apply to mental trouble, and especially the lighter sort of mental trouble - to irritate, to make angry by little provocations, to harass. It is used here, however, as is common in the Scriptures, in reference to torment or to anguish. The bones are the strength and framework of the body, and the psalmist means here to say that the very source of his strength was gone; that that which supported him was prostrated; that his disease and sorrow had penetrated the most firm parts of his body. Language is often used in the Scriptures, also, as if the "bones" actually suffered pain, though it is now known that the bones, as such, are incapable of pain. And in the same manner, also, language is often used, though that use of the word is not found in the Scriptures, as if the "marrow" of the bones were especially sensitive, like a nerve, in accordance with what is the common and popular belief, though it is now known that the marrow of the bones is entirely insensible to suffering. The design of the psalmist here is to say that he was crushed and afflicted in every part of his frame.

Have mercy - I have no merit. I deserve all I feel and all I fear.
O Lord, heal me - No earthly physician can cure my malady. Body and soul are both diseased, and only God can help me.
I am weak - אמלל umlal. I am exceedingly weak; I cannot take nourishment, and my strength is exhausted.
My bones are vexed - The disease hath entered into my bones.

Have mercy upon me, O LORD; for I [am] weak: O LORD, heal me; for my (b) bones are vexed.
(b) For my whole strength is abated.

Have mercy upon me, O Lord,.... He knew he was a sinner, both by original sin and actual transgression, which he was always ready to own; he knew that what he had done deserved the wrath of God, even his hot displeasure; and that for such things it came upon the children of disobedience: he knew that there was mercy with God through Christ, and therefore he flees unto it, pleads for it, and entreats the manifestation of forgiving love: he pleads no merits of his own, nor makes any mention of former works of righteousness done by him, but throws himself upon the mercy of God in Christ; giving this as a reason,
for I am weak; either in body, through some disease upon him; or in soul, being enfeebled by sin, and so without spiritual strength to do that which was good of himself; to exercise grace, and perform duty, and much less to keep the law of God, or make atonement for sin, or to bear the punishment of it;
O Lord, heal me; meaning either his body, for God is the physician of the body, he wounds and he heals; so he healed Hezekiah and others; and he should be sought to in the first place by persons under bodily disorders: or else his soul, as in Psalm 41:4; sin is the disease of the soul, and a very loathsome one it is, and is incurable but by the balm of Gilead, and the physician there; by the blood of Christ, and forgiveness through it; and the forgiveness of sin is the healing of the diseases of the soul, Psalm 103:3;
for my bones are vexed; with strong pain; meaning his body, as Kimchi and Aben Ezra observe; because these are the foundation of the body, and the more principal parts of it: and this may be understood of his grief and trouble of heart for his sins and transgressions, which is sometimes expressed by the bones being broke, and by there being no rest in them, Psalm 51:8.

I am weak--as a culled plant (Isaiah 24:4).
my bones--the very frame.
are vexed-- (Psalm 2:5) --shaken with fear.

Bones - My inmost parts.