Ibn Abbas reported: When the Prophet, peace and blessings be upon him, was expelled from Mecca, Abu Bakr said, “They have expelled their Prophet. Verily, unto Allah we belong and unto him we will return. They will surely be ruined. Then, it was revealed: Permission is given to those who are being fought because they were wronged, for Allah has power to support them (22:39). I knew that there would be fighting.” Ibn Abbas said, “It was the first verse to be revealed about fighting.”
Source: Sunan al-Nasā’ī 3085
Grade: Sahih (authentic) according to Al-Albani
عَنْ ابْنِ عَبَّاسٍ قَالَ لَمَّا أُخْرِجَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مِنْ مَكَّةَ قَالَ أَبُو بَكْرٍ أَخْرَجُوا نَبِيَّهُمْ إِنَّا لِلَّهِ وَإِنَّا إِلَيْهِ رَاجِعُونَ لَيَهْلِكُنَّ فَنَزَلَتْ أُذِنَ لِلَّذِينَ يُقَاتَلُونَ بِأَنَّهُمْ ظُلِمُوا وَإِنَّ اللَّهَ عَلَى نَصْرِهِمْ لَقَدِيرٌ فَعَرَفْتُ أَنَّهُ سَيَكُونُ قِتَالٌ قَالَ ابْنُ عَبَّاسٍ فَهِيَ أَوَّلُ آيَةٍ نَزَلَتْ فِي الْقِتَالِ
3085 سنن النسائي كتاب الجهاد باب وجوب الجهاد
3085 المحدث الألباني خلاصة حكم المحدث إسناده صحيح في صحيح النسائي