(O ye who believe! Take not the Jews and the Christians for friends…) [5:51].
Said ‘Atiyyah al-‘Awfi: “‘Ubadah ibn al-Samit went to see the Prophet and asked him: ‘O Messenger of Allah! I have numerous clients from amongst the Jews, who are ever ready to support me. However, I stand before Allah and His Messenger to absolve myself from the guardianship of the Jews. And I turn, instead, to Allah and His Messenger’. Hearing this, ‘Abd Allah ibn Ubayy said: ‘I am a man who fears the turn of events and will not absolve myself from the guardianship of the Jews’. The Messenger of Allah, Allah bless him and give him peace, then said: ‘O Abu’l-Hubab, that which you reserve to yourself of the guardianship of the Jews apart from ‘Ubadah ibn al-Samit is all yours and none of it is his’. He said: ‘I accept’. And so Allah, exalted is He, revealed about the two of them: (O ye who believe! Take not the Jews and the Christians for friends. They are friends one to another) up to His saying (And thou seest those in whose heart is a disease) [5:52], i.e. ‘Abd Allah ibn Ubayy (race toward them) for support (saying: We fear lest a change of fortune befall us)”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou