The Prophet of Allah, sallallaahu 'alayhi wa sallam, was eager to guide his uncle Abu Taalib:

Sa'eed ibn Al-Musayyab (a scholar) narrated that his father said: "When Abu Taalib was near death the Prophet of Allah, sallallaahu 'alayhi wa sallam, came to him, and he found Abu Jahl and'Abdullaah ibn Abu Umayyah ibn Al-Mugheerah sitting with his uncle. The Prophet of Allah, sallallaahu 'alayhi wa sallam, said to him: "O my uncle, say ‘None is worthy of being worshipped but Allah’, a statement that I will plead your case with in front of Allah," Abu Jahl and 'Abdullaah ibn Ummayah said: "Will you leave the religion of (your father) 'Abd Al-Muttalib!" The Prophet of Allah, sallallaahu 'alayhi wa sallam, continued to try to guide his uncle, and the other two would keep repeating that same statement, until Abu Taalib made his last statement that he was on the religion of 'Abd Al-Muttalib, and refused to bear witness to the oneness of Allah. So the Prophet of Allah, sallallaahu 'alayhi wa sallam, said when he died: "By Allah, I will continue to seek forgiveness for you as long as Allah does not forbid me to do so." Allah then revealed (what means): «It is not [proper] for the Prophet and those who have believed to ask forgiveness for the polytheists, even if they were relatives, after it has become clear to them that they are companions of Hellfire.» [Quran: 9:113] He also revealed to the Prophet of Allah, sallallaahu 'alayhi wa sallam, regarding Abu Taalib (what means): «Indeed, [O Muhammad], you do not guide whom you like, but Allah guides whom He wills.» [Quran: 28:56]”