The hadith reported from Sayyiduna Anas (may Allah be pleased with him) is in Sahih Muslim, and it is recorded in the book of Imam Muslim, together with all the reports describing the excellent character of the Messenger of Allah (peace and blessings be upon him) and his beautiful qualities, which whoever recognises would not find unlikely what we have mentioned in these two chapters, namely his kindness and mercy, along with the saying of Allah Almighty: "To the believers he is kind and merciful." [Surah al-Tawbah: 128]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3425