1)
What is the meaning of "Hashem Li b'Ozrai"?
1.
Radak: Hashem is with me, and He is with my helpers.
2)
What will he see in his haters?
1.
Radak: I will see what I want to see. This is like "uv'Oyvai Ra'asah Eini", "va'Tabet Eini b'Shurai" (54:9, 92:12).
2.
Malbim: Aside from protection, He will help me to defeat the enemy. Not only he cannot do evil to me - I will see vengeance on my haters.