God laughs at the two men one of whom kills the other; both of them will enter Paradise. They (the Companions) said: How, Messenger of Allah? He said: One is slain (in the way of Allah) and enters Paradise. Then God forgives the other and guides him to Islam; then he fights in the way of Allah and dies a martyr. (Using translation from Muslim 1890c)
وَقَالَ رَسُولُ اللهِ ﷺ يَضْحَكُ اللهُ لِرَجُلَيْنِ يَقْتُلُ أَحَدُهُمَا الْآخَرَ كِلَاهُمَا يَدْخُلُ الْجَنَّةَ قَالُوا كَيْفَ يَا رَسُولَ اللهِ؟ قَالَ يَقْتُلُ هَذَا فَيَلِجُ الْجَنَّةَ ثُمَّ يَتُوبُ اللهُ عَلَى الْآخَرِ فَيَهْدِيهِ إِلَى الْإِسْلَامِ ثُمَّ يُجَاهِدُ فِي سَبِيلِ اللهِ فَيُسْتَشْهَدُ