In a dream it is a sign of falling into something of Satan's work, and of a good outcome in his religion, because of His saying, the Exalted:
وَدَخَلَ ٱلْمَدِينَةَ عَلَىٰ حِينِ غَفْلَةٍ مِّنْ أَهْلِهَا فَوَجَدَ فِيهَا رَجُلَيْنِ يَقْتَتِلَانِ هَـٰذَا مِن شِيعَتِهِۦ وَهَـٰذَا مِنْ عَدُوِّهِۦ ۖ فَٱسْتَغَـٰثَهُ ٱلَّذِى مِن شِيعَتِهِۦ عَلَى ٱلَّذِى مِنْ عَدُوِّهِۦ فَوَكَزَهُۥ مُوسَىٰ فَقَضَىٰ عَلَيْهِ ۖ قَالَ هَـٰذَا مِنْ عَمَلِ ٱلشَّيْطَـٰنِ ۖ إِنَّهُۥ عَدُوٌّ مُّضِلٌّ مُّبِينٌ
“And he entered the city at a time of inattention by its people and found therein two men fighting: one from his faction and one from among his enemy. And the one from his faction called for help to him against the one from his enemy, so Moses struck him and [unintentionally] killed him. [Moses] said, "This is from the work of Satan. Indeed, he is a manifest, misleading enemy."”
Quran 28:15 · Saheeh International
to the end of the verse.