He wrote to his son, "To proceed: the Messenger of Allah ﷺ used to command us to set up places of prayer in our homes, to keep them well-maintained, and to keep them pure."
حدثنا محمد بن داود بن سفيان حدثنا يحيى يعني ابن حسان حدثنا سليمان بن موسى حدثنا جعفر بن سعد بن سمرة
أنه كتب إلى ابنه أما بعد فإن رسول الله ﷺ كان يأمرنا بالمساجد أن نصنعها في ديارنا ونصلح صنعتها ونطهرها
No references are available.
Its chain is daif. Tabarani reported it in Al-Kabir (7/252, no. 7026) from the hadith of Yahya Ibn Hassan through this route, and its chain is daif. The hadith has supporting narrations, among them the previous hadith. Habib is unknown, and Jafar bin Saad is daif, but the previous hadith renders this one unnecessary.