"I heard Al-Mughirah bin Shu'bah say: 'The Prophet (ﷺ) stood (in prayer at night) until his feet swelled up, and it was said to him: Allah has forgiven your past and future sins. He said: "Should I not be a thankful slave?'"
Sunan an-Nasa'i Book 20, Hadith 47
← Previous Hadith The Messenger of Allah (ﷺ) entered the masjid and saw a rope tied between two pillars. He said: "What is this?" They said: "It is for Zainab when she prays; if she gets tired she holds on to it." The Prophet (ﷺ) said: "Untie it. Let any one of you pray as long as he has energy, and if he gets tired let him sit down."

Sunan an-Nasa'i Book 20, Hadith 46 Next Hadith → "The Messenger of Allah (ﷺ) used to pray until he developed fissures in his feet."

Sunan an-Nasa'i Book 20, Hadith 48