Musnad Ahmad 28:442

'Affan narrated to us, Shu'bah narrated to us, he said: Ibrahim ibn Maymun informed me, he said: I heard a man from Banu al-Harith, he said: I heard a man among us who was called Ayyub, he said: I heard 'Abdullah ibn 'Amr saying: "Whoever repents before his death by a year, his repentance is accepted; and whoever repents before his death by a month, his repentance is accepted." Until he said: "A day." Until he said: "An hour." Until he said: "A moment (fawaq)." The man said: "What do you see if he was a polytheist and then accepted Islam?" He said: "I am only narrating to you as I heard from the Messenger of Allah, may Allah bless him and grant him peace, saying."