جَرِيءٌ مَتَى يُظْلَمْ يُعَاقِبْ بِظُلْمِهِ ۞ سَرِيعًا وَإِلَّا يَبْدِ بِالظُّلْمِ يَظْلِمِ
He is daring: when wronged, he retaliates swiftly; and if no wrong is done to him, he is apt to initiate wrongdoing himself.
Matā yuẓlam introduces a condition: the passive imperfect yuẓlam is jussive, and yuʿāqib is the result. Wa-illā opens the alternative case. The point is both this fighter’s extreme boldness and the alarming cycle in which retaliation can become unsolicited aggression.