John Calvin Commentary Psalms 26:6

"I will wash my hands in innocency: So will I compass thine altar, O Jehovah;" — Psalms 26:6 (ASV)

I will wash my hands in purity. Referring, in these words, to the ordinary use of the sacrifices, he makes a distinction between himself and those who professed to offer the same divine worship and thrust themselves forward in the services of the sanctuary, as if they alone had the sole right to perform them.

As David, therefore, and these hypocrites were alike in this respect, that they entered the sanctuary and surrounded the sacred altar together, he proceeds to show that he was a true worshipper, declaring that he not only diligently attended to the external rites, but came to worship God with unfeigned devotion.

It is obvious that he alludes to the solemn rite of washing which was practiced under the Law. Accordingly, he reproves the gross superstition of hypocrites, who, in seeking only the purification of water, neglected true purification; whereas God’s design in appointing the outward sign was to remind people of their inward pollution, and thus to encourage them to repentance.

The outward washing alone, instead of profiting hypocrites, kept them at a greater distance from God. When the Psalmist, therefore, says, I will wash my hands in innocence, he implies that they only gather more pollution and filth by their washings. The Hebrew word נקיון, nikkayon, signifies the cleanness of anything, and is figuratively used for innocence. Thus we see that, because hypocrites derive no moral purity whatever from their washings, David mocks the labor with which they vainly toil and torment themselves in such rites.

Therefore, however high the wicked may be exalted in the Church, and though crowds of them may fill our sanctuaries, let us, after David’s example, celebrate the outward profession of our faith in such a way as not to deceitfully substitute its external rites in place of true devotion. Thus we shall be pure and free from all stain of wickedness.

Moreover, as the people were not permitted to touch the altar, David uses the word encompass.