Sahih Muslim | Book 20 | Hadith Number 4660

Narrated by It has been
It has been reported on the authority of Abu Huraira that the Messenger of Allah (may peace be upon him) said: 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.