La-in basatta ilayya yadaka litaqtulanee ma ana bibasitin yadiya ilayka li-aqtulaka innee (surah Maidah: 28)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(5:28) Even if you stretch forth your hand against me to kill, I will not stretch forth my hand to kill you. *49 Surely, I fear Allah, the Lord of the entire universe.

La`im basatta ilaiya yadaka litaqtulanee maaa ana bibaasitiny yadiya ilaika li aqtulaka inneee akhaaful laaha Rabbal `aalameen

*49). This does not mean, that his brother assured him that when the latter stepped forward to kill him he would keep his hands tied and stretch out his own neck to be cut down rather than defend himself. What this statement amounts to is an assurance on the part of the first brother that, even though the other was intent on killing him, he himself had no such intention. In other words, he assured his brother that even though the latter was busy planning his murder he would not take the initiative in killing him despite his knowledge of the latter's intent.
*In view of the fact that the followers of all the Prophets are Muslims, the author has used a peculiarly Islamic term - caliphate, rather than kingship, etc. - to signify the predominantly religious (or shall we say, Islamic) quality of his rule and to distinguish it from systems of government not animated by the religious spirit - Ed.
Righteousness does not demand at all that when a man is subjected to wrongful aggression he should surrender to the aggressor rather than defend himself. Righteousness, however, demands that a man should not take the initiative and try to kill someone even though he knows him to be bent on killing him. He should rather wait for the act of aggression to be initiated by the other person. And this is exactly what was intended by the statement of the righteous son of Adam.