Sahih al-Bukhari — Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) — Hadith No: 4836
Translation
Narrated Al-Mughira:The Prophet (ﷺ) used to offer night prayers till his feet became swollen. Somebody said, to him," "Allah has forgiven you, your faults of the past and those to follow." On that, he said, "Shouldn't I be a thankful slave of Allah)?