﴿ وَقُل لِّعِبَادِى يَقُولُوا۟ ٱلَّتِى هِىَ أَحْسَنُ ۚ إِنَّ ٱلشَّيْطَٰنَ يَنزَغُ بَيْنَهُمْ ۚ إِنَّ ٱلشَّيْطَٰنَ كَانَ لِلْإِنسَٰنِ عَدُوًّۭا مُّبِينًۭا ﴾

“AND TELL My servants that they should speak in the most kindly manner [unto those who do not share their beliefs]: verily, Satan is always ready to stir up discord between men - for, verily, Satan is man's open foe!”

(Tell My bondmen) 'Umar and his fellow believers (to speak) to say to the disbelievers (that which is kindlier) i.e. greet them and be kind to them. (Lo! the devil soweth discord among them) when you treat them harshly. (Lo! the devil is for man an open foe) his enmity is quite manifest. This injunction was before they were commanded to fight.