Radak: It discusses a Rasha who thinks that there is no Master who will punish evil that he does. Therefore, it says Eved Hashem - the Resha'im's counsel is far from him. He is truly Eved Hashem; he knows that there is payment for good and evil.

Malbim: This Mizmor mentions the claims of the Yetzer ha'Ra and its enticements, how it prepares to shoot its arrows on the bow, in the darkness of its claims in the heart, and the answers that refute it. "La'Menatze'ach l'Eved Hashem" - this is how a servant of Hashem defeats his adversary.