وَإِذَا حُيِّيتُم بِتَحِيَّةٍ فَحَيُّوا بِأَحْسَنَ مِنْهَا أَوْ رُدُّوهَا ۗ إِنَّ اللَّهَ كَانَ عَلَىٰ كُلِّ شَيْءٍ حَسِيبًا (86)
(4:86) When you are greeted with a salutation then return it with a better one, or at least the same. *114 Surely Allah takes good count of everything.
*114). At that time the relations between the Muslims and non-Muslims were strained to the limit. It was feared, therefore, that the Muslims might feel inclined to treat the latter discourteously. They are accordingly asked to pay at least as much respect and consideration to others as is paid to them - and preferably more. Good manners and courtesy are to be matched by the Muslims. In fact, the mission entrusted to the Muslims requires them to excel others in this respect. Harshness, irritability and bitterness are not becoming in a people whose main function is to preach a message and invite people to it; a people committed to guiding mankind towards righteousness. While harshness and bitterness may at best satisfy one's injured vanity, they are positively harmful to the cause that one seeks to promote.'