I trust in thee - I depend upon thy infinite goodness and mercy for my support and salvation.
Let me not be ashamed - Hide my iniquity, and forgive my guilt.
O my God, I trust in thee - This is the first thought - a feeling that he had true confidence in God, and that in all the duties of life, in all his trials, and in all his hopes for the future, his reliance was on God alone.
Let me not be ashamed - That is, let me never be so forsaken by thee as to have occasion for shame that I have thus trusted in thee. The prayer is not that he might never be ashamed to avow and confess his trust in God, but that he might “find” God to be such a helper and friend that he might never be ashamed on account of the trust which he had put in Him, as if it had been a false reliance; that he might not be disappointed, and made to feel that he had done a foolish thing in confiding in One who was not able to help him. See the word explained in the notes at Job 6:20. Compare Isaiah 30:5; Jeremiah 8:9; Jeremiah 14:3-4.
Let not mine enemies triumph over me - This explains what the psalmist meant by his prayer that he might not be “ashamed,” or put to shame. He prayed that he might not be vanquished by his foes, and that it might not appear that he had trusted in a Being who was unable to defend him. Applied now to us, the prayer would imply a desire that we may not be so overcome by our spiritual foes as to bring dishonor on ourselves and on the cause which we profess to love; that we may not be held up to the world as those who are unable to maintain the warfare of faith, and exposed to scorn as those who are unfaithful to their trust; that we may not be so forsaken, so left to trial without consolation, so given over to sadness, melancholy, or despair, as to leave the world to say that reliance on God is vain, and that there is no advantage in being his friends.