﴿ قُل لِّلْمُخَلَّفِينَ مِنَ ٱلْأَعْرَابِ سَتُدْعَوْنَ إِلَىٰ قَوْمٍ أُو۟لِى بَأْسٍۢ شَدِيدٍۢ تُقَٰتِلُونَهُمْ أَوْ يُسْلِمُونَ ۖ فَإِن تُطِيعُوا۟ يُؤْتِكُمُ ٱللَّهُ أَجْرًا حَسَنًۭا ۖ وَإِن تَتَوَلَّوْا۟ كَمَا تَوَلَّيْتُم مِّن قَبْلُ يُعَذِّبْكُمْ عَذَابًا أَلِيمًۭا ﴾

“Say unto those bedouin who stayed behind: “In time you will be called upon [to fight] against people of great prowess in war: you will have to fight against them [until you die] or they surrender. And then, if you heed [that call], God will bestow on you a goodly reward; but if you turn away as you turned away this time, He will chastise you with grievous chastisement.””

Say to those of the Bedouins mentioned who were left behind to test them ‘You shall be called against a people possessed of great might — these are said to have been the tribe of Banū Hanīfa the inhabitants of the region of al-Yamāma; but it is also said that these were the Persians and the Byzantines — you shall fight them tuqātilūnahum is a circumstancial qualifier referring to an implied future situation which constitutes that to which the ‘call’ will be made; or they will submit so that you will not have to fight. So if you obey the command to fight them God will give you a good reward; but if you turn away like you turned away before He will chastise you with a painful chastisement’.