Majma al-Zawaid — Hadith 9570

Sayyiduna Khubayb bin Yasaf (may Allah be pleased with him) narrates: I came to the Prophet (peace and blessings be upon him) while he was setting out to take part in a battle; there was me and a man from my people, and we had not accepted Islam. We said: "We feel ashamed that the men of our people should take part in a battle and we not take part in it with them." The Prophet (peace and blessings be upon him) asked: "Have the two of you accepted Islam?" We said: "No." The Prophet (peace and blessings be upon him) said: "We will not seek the help of polytheists against polytheists." The narrator says: So we accepted Islam and took part in the battle with him. I killed a man, and he had struck me a blow. After that I married his daughter, and she used to say: "You had to deal with a man who gave you this wound," and I would say: "You have had to deal with a man who sent your father hastening to Hell."
Ahmad and Tabarani recorded it, and the narrators of both are thiqat (trustworthy).