O keep my soul - “My life;” or, keep “me.” The allusion is to all the perils which encompassed him, whether arising from his foes or his sins; and the prayer is, that the divine protection might be commensurate with the danger; that is, that he might not be destroyed, either by his enemies or by the sins which he had committed.
And deliver me - Save me; rescue me.
Let me not be ashamed - See Psalms 25:2.
For I put my trust in thee - This is urged as a reason why he should be delivered and saved. The idea seems to be, that the honor of God would be concerned in protecting one who fled to Him; who confided in Him; who relied on Him. Thus, when the helpless and the oppressed have so much confidence in our character and our ability as to fly to us in the time of trouble, it is a proper reason for them to ask our protection that they do confide in us. Our character becomes involved in the matter, and they may safely trust that we shall feel ourselves under obligations to act in conformity with the confidence reposed in us. It is thus that the poor and the oppressed confide in the good; thus that a sinner confides in God.