Verily I have cleansed my heart in vain - That is, There is no advantage in all my efforts to become pure and holy. It does not assist me in obtaining the favor of God; and it would be just as well to live a sinful life - to indulge in the pleasures of sense - to make the world my portion. Nothing is to be gained by all my painful efforts at self-discipline; by all my endeavors to become righteous. It would have been as well for me - or better - if I had lived a life of sin like other people. The righteous obtain from God fewer blessings than the wicked; they have less happiness and less prosperity in this world; they are subjected to more trouble and sorrow; and to all else there must be added the struggles, the conflict, the warfare, the painful effort "to be" pure, and to lead a holy life, all of which is now seen to be of no advantage whatever. Such thoughts as these were not confined to the psalmist. They are thoughts which will start up in the mind, and which it is not easy to calm down.
And washed my hands in innocency - That is, It has been of no use that I have washed my hands in innocency. The word "innocency" here means "purity." He had washed his hands in that which was pure; as, pure water. To wash the hands is emblematic of innocence or purity. See the notes at Psalm 26:6.

I have cleansed my heart in vain - It is no advantage to us to worship the true God, to walk according to the law of righteousness, and keep the ordinances of the Most High.

Verily, I have cleansed my heart in vain,.... Which supposes that his heart had been unclean, as every man's is, and which appears by what is in it, and by what comes out of it; that it was now cleansed, not in an absolute and legal sense, as if it was wholly free from sin, for this no man can say; but in an evangelical sense, being purified by faith in the blood of Christ; that he had himself some concern in the cleansing of his heart, which seems to be contrary to Proverbs 20:9 and besides, this is the Lord's own work, Psalm 51:10 wherefore this may be considered as a wrong and rash expression of his; for as he was wrong in one part of it, its being cleansed in vain, so he might be in the other, in ascribing it to himself; though it may be allowed, consistent with what is before observed, that a believer has a concern in the cleansing of his heart; for, being convinced of the impurity of it, he owns and laments it before the Lord; and, seeing the fountain of the Redeemer's blood opened, he applies to it, and to him for cleansing; and expresses a love unto, a great and studious concern for purity of heart as well as life; and, under the influence of divine grace, is enabled to keep a watch over it, whereby, through the same grace, it is preserved from much pollution; and by fresh application to the blood of Christ, is cleansed from what it daily contracts:
and washed my hands in innocency: that is, "in vain", as before; which denotes the performance of good works, a course of holy life and conversation, which when right springs from purity of heart; See Gill on Psalm 26:6, now the psalmist under temptation concluded that all his religion and devotion were in vain, all his hearing, and reading, and attending on ordinances, all his concern for purity of heart and life; since those who showed no regard to these things prospered in the world, and increased in riches, abounded in ease and plenty, and seemed to be rather the favourites of heaven than religious men; and this temptation was strengthened by the following observation.

The Psalmist, partaking of these troubles, is especially disturbed in view of his own case, that with all his diligent efforts for a holy life, he is still sorely tried.

In vain - Hence I was sometimes tempted, to think that religion was a vain, unprofitable thing. True religion is here described by its two principal parts, the cleansing of the heart, and the hands.