Psalm 25:2

O my God, I trust in thee
He claims his interest in God, and expresses his faith and confidence in him, in the midst of all his troubles; (See Gill on Psalms 7:1);

let me not be ashamed;
meaning of his trust in God, by being disappointed of the help, deliverance, and salvation from him, which he trusted in him for; and the believer, as he has no reason to be ashamed of God, the object of his trust; so neither of the act of his hope or trust in him; nor shall he; for hope makes not ashamed; see ( Psalms 119:116 ) ( Romans 5:5 ) ;

let not mine enemies triumph over me;
either his temporal enemies, his subjects that were risen up against him; or his spiritual enemies, Satan, and the men of the world, who rejoice and triumph when the saints are forsaken by God; and they are ready to say, as David's enemies did of him, there is no help or salvation for him in God, ( Psalms 3:2 ) ; and when they fall into their hands, or fall by them.