For day and night thy hand was heavy upon me. In this verse he explains more fully whence such heavy grief arose; namely, because he felt the hand of God to be sore against him. The greatest of all afflictions is to be so heavily pressed with the hand of God, that the sinner feels he has to do with a Judge whose indignation and severity involve in them many deaths, besides eternal death. David, accordingly, complains that his moisture was dried up, not merely from simply meditating on his sore afflictions, but because he had discovered their cause and spring. The whole strength of men fails when God appears as a Judge and humbles and lays them prostrate by exhibiting the signs of his displeasure. Then is fulfilled the saying of Isaiah, "The grass withereth, the flower fadeth, because the Spirit of the Lord bloweth upon it." (Isaiah 40:7) The Psalmist, moreover, tells us, that it was no common chastisement by which he had been taught truly to fear the divine wrath; for the hand of the Lord ceased not to be heavy upon him both day and night. From a child, indeed, he had been inspired with the fear of God, by the secret influence of the Holy Spirit, and had been taught in true religion and godliness by sound doctrine and instruction. And yet so insufficient was this instruction for his attainment of this wisdom, that he had to be taught again like a new beginner in the very midst of his course. Yea, although he had now been long accustomed to mourn over his sins, he was every day anew reduced to this exercise, which teaches us, how long it is ere men recover themselves when once they have fallen; and also how slow they are to obey until God, from time to time, redouble their stripes, and increase them from day to day. Should any one ask concerning David, whether he had become callous under the stripes which he well knew were inflicted on him by the hand of God, the context furnishes the answer; namely, that he was kept down and fettered by perplexing griefs, and distracted with lingering torments, until he was well subdued and made meek, which is the first sign of seeking a remedy. And this again teaches us, that it is not without cause that the chastisements by which God seems to deal cruelly with us are repeated, and his hand made heavy against us, until our fierce pride, which we know to be un-tameable, unless subdued with the heaviest stripes, is humbled.

For day and night - I found no relief even at night. The burden was constant, and was insupportable.
Thy hand was heavy upon me - Thy hand seemed to press me down. It weighed upon me. See Job 13:21; Psalm 39:10. It was the remembrance of guilt that troubled him, but that seemed to him to be the hand of God. It was God who brought that guilt to his recollection; and God "kept" the recollection of it before his mind, and on his heart and conscience, so that he could not throw it off.
My moisture - The word used here - לשׁד leshad - means properly "juice" or "sap," as in a tree; and then, "vital-moisture," or, as we should say, "life-blood." Then it comes to denote vigour or strength.
Is turned into the drought of summer - Is, as it were, all dried up. I am - that is, I was at the time referred to - like plants in the heat of summer, in a time of drought, when all moisture of rain or dew is withheld, and when they dry up and wither. Nothing could more strikingly represent the distress of mind under long-continued conviction of sin, when all strength and vigour seem to waste away.

For day and night thy hand was heavy upon me,.... Meaning the afflicting hand of God, which is not joyous, but grievous, and heavy to be borne; especially without his gracious presence, and the discoveries of his love: this continued night and day, without any intermission; and may design some violent distemper; perhaps a fever; since it follows,
my moisture is turned into the drought of summer. That is, the radical moisture in him was almost dried up, as brooks in the summer season; his body was parched, as it were, with the burning heat of the disease; or with an apprehension of the wrath of God under it, or both: and so he continued until be was brought to a true sense of sin, and an acknowledgment of it, when he had the discoveries of pardoning love, as is expressed in Psalm 32:5. The Septuagint and Vulgate Latin versions read, "I am turned into distress, through a thorn being fixed"; and so Apollinarius paraphrases the words,
"I am become miserable, because thorns are fixed in my skin;''
reading for and which Suidas (o) interprets "sin", that being like the thorn, unfruitful and pricking; see 2-Corinthians 12:7.
Selah; on this word; see Gill on Psalm 3:2.
(o) In voce

thy hand--of God, or power in distressing him (Psalm 38:2).
moisture--vital juices of the body, the parching heat of which expresses the anguish of the soul. On the other figures, compare Psalm 6:2, Psalm 6:7; Psalm 31:9-11. If composed on the occasion of the fifty-first Psalm, this distress may have been protracted for several months.

Hand - Thy afflicting hand. My moisture - Was dried up.