She married Abū Lahab, a paternal uncle of Muhammad. They had at least six children: Utbah, Utaybah, Muattab, Durrah (Fakhita), 'Uzzā and Khālida. It is not clear whether she was also the mother of Abu Lahab's son Durrah.
Umm Jamil supported her husband in his opposition to Muhammad's preaching. When Muhammad promised Paradise to the believers, Abu Lahab blew on his hands and said, "May you perish. I can see nothing in you of the things that Muhammad says." Muhammad therefore declared a revelation from Allah about them.
May the hands of Abu Lahab be ruined, and ruined is he.
His wealth will not avail him or that which he gained.
He will burn in a Fire of flame
And his wife – the carrier of firewood.
Around her neck is a rope of fibre.
The occasion for this revelation is disputed. Ibn Sa'd and Ibn Kathir state that it was in 613 CE, when Muhammad summoned the Quraysh to Mount Safa for his first public warning that they must heed Allah's message. Abu Lahab interrupted: "May you perish! Did you assemble us for this?" and Muhammad responded with the prophecy. Ibn Ishaq implies that it occurred in 616, when Abu Lahab left the Hashim clan and refused to protect Muhammad.
Ibn Ishaq says that Umm Jamil was called "the carrier of firewood" because she carried thorns and cast them in Muhammad's way where he would be passing; however, he also states that the Quraysh did not resort to this form of harassment until after the death of Abu Talib in 620. Ibn Kathir also offers the alternative theory that "carrier of firewood" does not refer to a past event but to Umm Jamil's future destiny of willingly stoking the fires that would punish her husband in Hell.
When Umm Jamil bint Harb heard that Muhammad had been prophesying about her and her husband, she went to the Kaaba, where Muhammad was sitting with Abu Bakr, carrying a stone pestle. She did not notice Muhammad, so she asked Abu Bakr after him, "for I have been told that he is satirising me. If I had found him, I would have smashed his mouth with this stone." Then she produced a poem of her own:
We reject the reprobate,
His words we repudiate,
His religion we loathe and hate.
She departed, still not having noticed Muhammad.