The Prophet ﷺ commanded us to respond to the salutation of the imam. and to love each other, and to salute each other.  

أَمَرَنَا النَّبِيُّ ﷺ أَنْ نَرُدَّ عَلَى الإِمَامِ وَأَنْ نَتَحَابَّ وَأَنْ يُسَلِّمَ بَعْضُنَا عَلَى بَعْضٍ