Hadithcore
Al-Adab Al-Mufrad, 1121
sahih· Al-Albani

Hisham ibn 'Urwa said, "I saw some of the letters of the Prophet, (ﷺ). After the introduction he said, 'Following on from that'"

حَدَّثَنَا رَوْحُ بْنُ عَبْدِ الْمُؤْمِنِ، قَالَ‏:‏ حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ هِشَامِ بْنِ عُرْوَةَ قَالَ‏:‏ رَأَيْتُ رَسَائِلَ مِنْ رَسَائِلِ النَّبِيِّ صلى الله عليه وسلم، كُلَّمَا انْقَضَتْ قِصَّةٌ قَالَ‏:‏ أَمَّا بَعْدُ‏.‏

References2 variants
In-Book Reference
Book 45, Hadith 5
English Reference
Book 45, Hadith 1121