Narrated Zaid bin Arqam:
While I was taking part in a Ghazwa. I heard 'Abdullah bin Ubai (bin Abi Salul) saying. "Don't spend on those who are with Allah's Apostle, that they may disperse and go away from him. If we return (to Medina), surely, the more honorable will expel the meaner amongst them." I reported that (saying) to my uncle or to 'Umar who, in his turn, informed the Prophet of it. The Prophet called me and I narrated to him the whole story. Then Allah's Apostle sent for 'Abdullah bin Ubai and his companions, and they took an oath that they did not say that. So Allah's Apostle disbelieved my saying and believed his. I was distressed as I never was before. I stayed at home and my uncle said to me. "You just wanted Allah's Apostle to disbelieve your statement and hate you." So Allah revealed (the Sura beginning with) 'When the hypocrites come to you.' (63.1) The Prophet then sent for me and recited it and said, "O Zaid! Allah confirmed your statement."
Sahih al-Bukhari, Vol. 6, Book of Prophetic Commentary on the Qur'an, Hadith 423
Sahih al-Bukhari, Book of Prophetic Commentary on the Qur'an, Hadith 423