Preserve my soul - Preserve, or keep, my life; for so the word rendered soul means in this place, as it does commonly in the Scriptures.
For I am holy - Margin, “One whom thou favorest.” The Hebrew word - חסיד châsı̂yd - means properly, benevolent, kind; then, good, merciful, gracious; and then pious, godly. Psalms 30:4; Psalms 31:23; Psalms 37:28. The ground of the plea here is, that he was a friend of God; and that it was proper on that account to look to him for protection. He does not say that he was holy in such a sense that he had a claim on that account to the favor of God, or that his personal holiness was a ground of salvation; but the idea is, that he had devoted himself to God, and that it was, therefore, proper to look to him for his protection in the time of danger. A child looks to a parent for protection, because he is a child; a citizen looks to the protection of the laws, because he is a citizen; and so the people of God may look to him for protection, because they are his people. In all this there is no plea of merit, but there is the recognition of what is proper in the case, and what may he expected and hoped for.
Save thy servant - Save him from threatening danger and from death.
That trusteth in thee - Because I trust or confide in thee. I go nowhere else for protection; I rely on no one else. I look to thee alone, and I do this with entire confidence. A man who does this has a right to look to God for protection, and to expect that God will interpose in his behalf.