حَدَّثَنَا يَحْيَى بْنُ بِشْرٍ، قَالَ: حَدَّثَنَا الْحَكَمُ بْنُ الْمُبَارَكِ، قَالَ: حَدَّثَنَا عَبَّادٌ يَعْنِي ابْنَ عَبَّادٍ، عَنْ عَاصِمٍ الأَحْوَلِ، عَنْ أَبِي عُثْمَانَ النَّهْدِيِّ
قَالَ: كَتَبَ أَبُو مُوسَى إِلَى رُهْبَانٍ يُسَلِّمُ عَلَيْهِ فِي كِتَابِهِ، فَقِيلَ لَهُ: أَتُسَلِّمُ عَلَيْهِ وَهُوَ كَافِرٌ؟ قَالَ: إِنَّهُ كَتَبَ إِلَيَّ فَسَلَّمَ عَلَيَّ، فَرَدَدْتُ عَلَيْهِ
“Abu Musa wrote to a Persian grandee and greeted him in his letter. He was asked, ‘Do you greet him when he is an unbeliever?’ He replied, ‘He wrote to me and greeted me, so I have answered him.’”
Al-Adab Al-Mufrad 1104, Book 44, The People of the Book, Hadith 1. 1 min read