ENOfficial
Samura said, “God’s Messenger commanded us to respond to the imam, to love one another, and to salute one another.” Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ سَمُرَةَ قَالَ: أَمَرَنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنْ نَرُدَّ عَلَى الْإِمَامِ وَنَتَحَابَّ وَأَنْ يُسَلِّمَ بَعْضُنَا عَلَى بَعْضٍ. رَوَاهُ أَبُو دَاوُد
sunnah.com