What does Psalm 25:3 mean?

Here David expresses his confidence that the Lord will come to his assistance. He will not allow David's foes to triumph over him and thereby disgrace him. David also includes all who hope in the Lord and await the fulfillment of His promises as being protected from disgrace by the Lord. To the contrary, the Lord will put to shame all those who treacherously oppose the righteous without provocation.

In all periods of history believers may trust the Lord to vindicate them and upset the treacherous plans of their opponents. The story of Job demonstrates this truth. The Devil schemed to destroy Job's faith by hurling all kinds of trials at him, including the ordeal of Job's wife suggesting that he curse God and die (Job 2:9). But ultimately God vindicated Job. He rebuked Job's so-called friends for judging him (Job 42:7), and he called Job "his servant" (Job 42:7, 8), and blessed "the latter days of Job more than his beginning" (Job 42:12).

Even those who do not live—on earth—to see their vindication have confidence that God is in control and working all things for a good end (Hebrews 11:13–16).