‘Urwah ibn Ruwaym reported: I saw Abu Umamah al-Bahili, may Allah be pleased with him, greet with peace whomever he would meet among the Muslims and non-Muslim citizens. Abu Umamah would say, “This is the greeting for the people of our religion, an assurance of security for the people of our covenant, and the name among the names of Allah that we share between us.”
Source: al-Tamhīd 17/91
عَنْ عُرْوَةَ بْنِ رُوَيْمٍ قَالَ رَأَيْتُ أَبَا أُمَامَةَ الْبَاهِلِيَّ رضي الله عنه يُسَلِّمُ عَلَى كُلِّ مَنْ لَقِيَ مِنْ مُسْلِمٍ وَذِمِّيٍّ وَيَقُولُ هِيَ تَحِيَّةٌ لِأَهْلِ مِلَّتِنَا وَأَمَانٌ لِأَهْلِ ذِمَّتِنَا وَاسْمٌ مِنْ أَسْمَاءِ اللَّهِ نُفْشِيهِ بَيْنَنَا
17/91 التمهيد لما في الموطأ من المعاني والأسانيد