“Plead my cause, O LORD, with them that strive with me: fight against them that fight against me.” Psalm 35:1 (KJV)
Titled as “A Psalm of David” we can assume that at least one of his enemies was king Saul. David never lifted a hand against Saul. Saul was his king. David loved Saul. Saul did not, however, love David.
Like David we, as Christians, are to love our enemies (Matthew 5:44; Luke 6:27, 35), and trust that the LORD will deal with them in His own way.
It does not seem, by this verse, that David considered anyone his enemy. He just asked the LORD, “Plead my cause…” and “Fight against them…” It is a tough thing sometimes not to strike back when we are attacked, by words, accusations, or physically assaulted; but the child of God needs to remember what God says, “Vengeance is Mine, I will repay” (Romans 12:19).
Let the LORD God do your fighting. He handles it so much better.