When the Prophet ﷺ was driven out of Mecca, Abu Bakr said, "They have driven out their Prophet. Indeed, to Allah we belong and to Him we shall return. They will surely perish."Then the verse was revealed, "Permission has been given to those who are being fought, because they were wronged. And indeed, Allah is competent to give them victory" [Hajj 22:39].He said, "By this I knew there would be fighting."Ibn Abbas said, "This is the first verse revealed concerning fighting."
حدثنا إسحاق حدثنا سفيان عن الأعمش عن مسلم البطين عن سعيد بن جبير
لما أخرج النبي ﷺ من مكة قال أبو بكر أخرجوا نبيهم إنا لله وإنا إليه راجعون ليهلكن فنزلت {أذن للذين يقاتلون بأنهم ظلموا وإن الله على نصرهم لقدير} قال فعرف أنه سيكون قتال قال ابن عباس هي أول آية نزلت في القتال
Its chain of transmission is sahih. Tirmidhi related it, 4:151, through Ishaq bin Yusuf, and he said, a hasan hadith, and it has been related by more than one narrator from Sufyan, from Amash, from Muslim Batin, from Saeed bin Jubayr, as a mursal report, without Ibn Abbas mentioned in it. It seems he intends by this to point out a defect in the hadith, and that is why he only graded it hasan, but this is not actually a defect, since connecting the chain is an addition from a trustworthy narrator. Ibn Kathir quoted it in his tafsir, 5:592, from Ibn Jareer, then also attributed it to Nasai and Ibn Abu Hatim.Udhina, with the hamzah pronounced as fatha or damma, both readings are valid. Yuqatiluna, with the ta pronounced as fatha or kasrah, both readings are also valid.