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
← Previous Hadith The Prophet (ﷺ) came in to her and there was a woman with her. He said: "Who is this?" She said: "So-and-so, and she does not sleep." And she told him about how she prayed a great deal. He said: "Stop praising her. You should do what you can, for by Allah (SWT), Allah never gets tired (of giving reward) until you get tired. And the most beloved of religious actions to Him is that in which a person persists."

Sunan an-Nasa'i Book 20, Hadith 45 Next Hadith → "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