Companion Mu'adh bin Jabal was a prominent Ansar companion who converted to Islam at 18. The Prophet described him as the most knowledgeable in his nation regarding the lawful (halal) and prohibited (haram) and sent him as a teacher and judge to Yemen. He compiled the Quran during the Prophet's lifetime. He died of the Amwas Plague in Jordan in 18 AH at the age of 38. His tomb is in Al-Shuna al-Shamaliyya, Irbid.