It is narrated from Sayyiduna Rafi' bin Khadij (may Allah be pleased with him) that he went out (to the battlefield) on the day of Uhud, and the Prophet (peace and blessings be upon him), considering him too young, wanted to send him back. At this his paternal uncle said: O Messenger of Allah, he is an archer. So he (peace and blessings be upon him) let him go out (to the battlefield). Then an arrow struck him in the chest or the throat, and his uncle came to the Prophet (peace and blessings be upon him) and said: My nephew has been struck by an arrow. The Messenger of Allah (peace and blessings be upon him) said: "If you leave it in him and he dies, he will die a martyr." Abdullah bin Husayn said: His wife told me that she would see him bathing and (the arrowhead) would move in his chest.
Hadith Referenceالمعجم الكبير للطبراني / باب الراء / 4226