Al-Adab Al-Mufrad, Book 43, Hadith 1076 (English) ⓘ
Abu Hurayra reported that the Prophet, may Allah bless him and grant him peace, said, "A man's messenger to another man is his permission to enter."
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، قَالَ: حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ حَبِيبٍ، وَهِشَامٍ، عَنْ مُحَمَّدٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ: رَسُولُ الرَّجُلِ إِلَى الرَّجُلِ إِذْنُهُ.
also referenced under: Hadith 1076 (Reference) & Book 43, Hadith 26 (In-Book)