"Say to the ones who remained behind among the Bedouins: 'You will be called to a people of great military might'"—and al-ba's (might) is fighting.
"'You will fight them or they will submit'"—meaning: you will fight them for [the sake of] Islam.
Al-Hasan and Mujahid said: They are the people of Persia. "'So if you obey, Allah will give you a good reward; but if you turn away as you turned away before'"—Al-Kalbi said: [Meaning] on the day of Hudaybiyyah.
﴿قُلْ لِلْمُخَلَّفِينَ مِنَ الأَعْرَابِ سَتُدْعَوْنَ إِلَى قَوْمٍ أُولِي بَأْسٍ شَدِيدٍ﴾ والبأس: الْقِتَال.
﴿تُقَاتِلُونَهُمْ أَوْ يُسْلِمُونَ﴾ أَي: تقاتلونهم على الْإِسْلَام.
قَالَ الْحسن وَمُجاهد: هم أهل فَارس ﴿فَإِنْ تُطِيعُوا يُؤْتِكُمُ اللَّهُ أَجْرًا حَسَنًا وَإِنْ تَتَوَلَّوْا كَمَا تَوَلَّيْتُمْ من قبل﴾ قَالَ الْكَلْبِيّ: يَوْم الْحُدَيْبِيَة.
