Adam Clarke on Psalms 26:6

I will wash mine hands in innocency - Washing the hands was frequent among the Jews, and was sometimes an action by which a man declared his innocence of any base or wicked transaction. This Pilate did, to protest his innocence of the mal-treatment and death of Christ. I will maintain that innocence of life in which I have hitherto walked; and take care that nothing shall be found in my heart or life that would prevent me from using the most holy ordinance, or worshipping thee in spirit and truth.

So wilt I compass thine altar - It is a mark of respect among the Hindoos to walk several times round a superior, and round a temple.