Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says that the Messenger of Allah (peace and blessings be upon him) sought help from the Jews of Banu Qaynuqa' and gave them some property as a gift in return, but did not give them a fixed share.
Only al-Hasan bin Umarah narrated this, and he is matruk (abandoned). No authentic hadith on this has reached us, and we have narrated before this (reports) on the dislike of seeking help from the polytheists.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17970
Al-Zuhri (may Allah have mercy on him) says that the Messenger of Allah (peace and blessings be upon him) fought together with some Jewish people and also allotted them a share.
Imam al-Shafi'i (may Allah have mercy on him) says that this hadith is munqati' (broken), so it is not a proof.
The Shaykh (may Allah have mercy on him) says: Futayr al-Harithi says that the Messenger of Allah (peace and blessings be upon him) took ten Jews of Madinah with him to Khaybar and allotted them a share like the Muslims. This too is munqati', and its chain is weak.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17971