Quran english Al Fath 16

قل للمخلفين من الأعراب ستدعون إلى قوم أولي بأس شديد تقاتلونهم أو يسلمون فإن تطيعوا يؤتكم الله أجرا حسنا وإن تتولوا كما توليتم من قبل يعذبكم عذابا أليما

Qul lilmukhallafeena mina al-aAArabisatudAAawna ila qawmin olee ba/sin shadeedin tuqatiloonahumaw yuslimoona fa-in tuteeAAoo yu/tikumu Allahuajran hasanan wa-in tatawallaw kama tawallaytum minqablu yuAAaththibkum AAathaban aleema

 
Sahih International
Say to those who remained behind of the bedouins, “You will be called to [face] a people of great military might; you may fight them, or they will submit. So if you obey, Allah will give you a good reward; but if you turn away as you turned away before, He will punish you with a painful punishment.”
Muhsin Khan
Say (O Muhammad SAW) to the bedouins who lagged behind: “You shall be called to fight against a people given to great warfare, then you shall fight them, or they shall surrender. Then if you obey, Allah will give you a fair reward, but if you turn away as you did turn away before, He will punish you with a painful torment.”
Pickthall
Say unto those of the wandering Arabs who were left behind: Ye will be called against a folk of mighty prowess, to fight them until they surrender; and if ye obey, Allah will give you a fair reward; but if ye turn away as ye did turn away before, He will punish you with a painful doom.
Yusuf Ali
Say to the desert Arabs who lagged behind: “Ye shall be summoned (to fight) against a people given to vehement war: then shall ye fight, or they shall submit. Then if ye show obedience, Allah will grant you a goodly reward, but if ye turn back as ye did before, He will punish you with a grievous Penalty.”
Shakir
Say to those of the dwellers of the desert who were left behind: You shall soon be invited (to fight) against a people possessing mighty prowess; you will fight against them until they submit; then if you obey, Allah will grant you a good reward; and if you turn back as you turned back before, He will punish you with a painful punishment.
Dr. Ghali
Say to the Arabs (of the desert) who were left behind, “You will soon be called against a people endowed with strict violence to fight them, or they surrender. So, in case you obey, Allah will bring you a fair reward, and in case you turn away, as you did turn away earlier, He will torment you with a painful torment.”