وَدَخَلَ الْمَدِينَةَ عَلَى حِينِ غَفْلَةٍ مِّنْ أَهْلِهَا فَوَجَدَ فِيهَا رَجُلَيْنِ يَقْتَتِلَانِ هَذَا مِن شِيعَتِهِ وَهَذَا مِنْ عَدُوِّهِ فَاسْتَغَاثَهُ الَّذِي مِن شِيعَتِهِ عَلَى الَّذِي مِنْ عَدُوِّهِ فَوَكَزَهُ مُوسَى فَقَضَى عَلَيْهِ قَالَ هَذَا مِنْ عَمَلِ الشَّيْطَانِ إِنَّهُ عَدُوٌّ مُّضِلٌّ مُّبِينٌ
[One day] he entered the city at a time when its people were not likely to take notice. He found there two men fighting, this one from among his followers, and that one from his enemies. The one who was from his followers sought his help against him who was from his enemies. So Moses hit him with his fist, whereupon he expired. He said, ‘This is of Satan’s doing. Indeed he is clearly a misguiding enemy.’
Agha Ali Puya Commentary
Commentary on Quran 28:15
[Pooya/Ali Commentary 28:15] One day, Musa found an Egyptian cook of Firawn beating a poor helpless Jew who sought Musa's help. Musa asked the Egyptian to spare the poor Jew but he did not cease beating him whereupon Musa gave a blow to make him stay away from the Jew but the Egyptian fell dead. Musa had killed the offender in an effort to help the oppressed Jew, but fearing that Egyptians would retaliate for the death of a fellow Egyptian, Musa prayed to Allah to keep his deed hidden from the men of Firawn. Faghfir-li here means "protect me".