Lady Umm Salamah (may Allah be pleased with her) narrates that once I was sitting with the Prophet Muhammad (peace be upon him), when two men came to him. There was a dispute between them regarding inheritance, concerning some things that were very old. The Prophet Muhammad (peace be upon him) said: "I will judge between you according to my opinion in matters about which no revelation has been sent down to me. So, if I give a decision in favor of someone, and as a result he takes something unjustly, then he is taking a piece of Hell, which he will carry around his neck on the Day of Resurrection." The narrator says that both of those men began to weep. One of them said: The right I was claiming actually belongs to my companion. The Prophet Muhammad (peace be upon him) said: "No! Both of you go and investigate the matter, then take your respective shares, and each of you should declare it lawful for his companion."