Seeking help from the polytheists

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).

Sayyiduna Abu Humayd al-Sa'idi (may Allah be pleased with him) narrates: On the occasion of the Battle of Uhud the Prophet (peace and blessings be upon him) set out, until, when he had passed Thaniyyat al-Wada', there was a military detachment there. He asked: "Who are these people?" The people said: "This is Abdullah bin Ubayy with six hundred of his allies (mawali) from the Jews of Banu Qaynuqa'." The Prophet (peace and blessings be upon him) asked: "Have these people accepted Islam?" The people said: "No, O Messenger of Allah!" The Prophet (peace and blessings be upon him) said: "Tell them to go back, for we will not seek help from polytheists against polytheists."
Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat. Its chain contains Sa'd bin al-Mundhir bin Abi Humayd, whom Ibn Hibban mentioned in Kitab al-Thiqat, saying: "This is Sa'd bin Abi Humayd," so he attributed him to his grandfather. The rest of its narrators are thiqat (trustworthy).