Sahih Bukhari, Chapter: Funerals (Al-Janaaiz)

When Abdullah bin Ubai bin Salul died, Allah's Apostle (p.b.u.h) was called upon to offer his funeral prayer. When Allah's Apostle stood up to offer the prayer, I got up quickly and said, "O Allah's Apostle! Are you going to pray for Ibn Ubai and he said so and so on such and such occasions?" And started mentioning all that he had said. Allah's Apostle smiled and said, "O 'Umar! Go away from me." When I talked too much he said, "I have been given the choice and so I have chosen (to offer the prayer). Had I known that he would be forgiven by asking for Allah's forgiveness for more than seventy times, surely I would have done so." ('Umar added): Allah's Apostle offered his funeral prayer and returned and after a short while the two verses of Surah Tawba' were revealed: i.e. "And never (O Muhammad) pray for any of them who dies . . . (to the end of the verse) rebellion (9.84)" -- ('Umar added), "Later I astonished at my daring before Allah's Apostle on that day. And Allah and His Apostle know better."