Narrated Ibn 'Abbas:"When the Prophet (ﷺ) was expelled from Makkah, Abu Bakr said: 'They have driven out their Prophet to their own doom.' So Allah, Most High, revealed: 'Permission (to fight) is given to those who are fought against, because they have been wronged; and surely, Allah is able to give them victory (22:39).' So Abu Bakr said: 'Then I knew that there would be fighting

English translation · Jami' at-Tirmidhi