Musnad Ahmad 32:1846

Mu'awiyah ibn 'Amr narrated to us, Za'idah narrated to us, 'Abdullah ibn 'Abdur-Rahman ibn Ma'mar al-Ansari narrated to us, he said: I heard Anas ibn Malik saying: The Messenger of Allah (peace and blessings of Allah be upon him) reclined at the house of the daughter of Milhan. He said: Then he raised his head and laughed. She said: "What are you laughing at, O Messenger of Allah?" He said: "Some people from my nation who ride this green sea, fighting in the way of Allah, their likeness is like the kings upon thrones." She said: "Supplicate to Allah, O Messenger of Allah, that He makes me one of them." He said: "O Allah, make her one of them." She married 'Ubadah ibn as-Samit. He said: So she rode upon the sea with the daughter of Qurzah. When she returned, she mounted a beast of hers on the shore, and it stumbled with her, so she fell and died.