Allah, Glorified and Exalted, laughs at two men, one of them kills the other, yet both enter Paradise. This one fights in the cause of Allah, so he gets killed. Then Allah accepts the repentance of the killer, so he becomes a Muslim and dies as a martyr

Explanation

This Hadīth indicates that Allah laughs at two men. Although one of them kills the other, both will enter Paradise. A Muslim fights in the cause of Allah to elevate the word of Allah, yet he gets killed by a disbeliever, so he enters Paradise. Later Allah accepts the repentance of the killer, so he accepts Islam. Then he fights in the cause of Allah and dies as a martyr.