The Messenger of Allah ﷺ was asked, "Which prayer is best after the obligatory prayers?"He replied, "Prayer in the depth of the night."He was then asked, "Which fasting is best after Ramadan?"He answered, "The month of Allah which you call Muharram."
حدثنا عبد الرحمن وأبو سعيد قالا حدثنا زائدة حدثنا عبد الملك بن عمير عن محمد بن المنتشر عن حميد بن عبد الرحمن
سئل رسول الله ﷺ أي الصلاة أفضل بعد المكتوبة قال الصلاة في جوف الليل قيل أي الصيام أفضل بعد رمضان قال شهر الله الذي تدعونه المحرم
Its isnad is sahih. Zaida is Ibn Qudama Thaqafi. Humayd bin Abdul-Rahman is al-Humayri al-Basri. His reliability was established earlier at 1440, and we add here that Bukhari gave his biography in al-Kabir 1/2/343-344, as did Ibn Saad 7/1/107, and Ibn Abu Hatim 1/2/225.The hadith was narrated by Muslim 1:322-323, by way of Jareer and by way of Zaida, both of them from Abdul-Malik bin Umayr, with this same chain. It also appears in Jami al-Masanid 7:18-19, where it is mentioned that it was also narrated by Abu Dawud, Tirmidhi, Nasai, and Ibn Majah. Tirmidhi said, hasan sahih.