Musnad Ahmad 583:0

Narrated by Abdullah ibn Abi Habibah: I saw the Messenger of Allah (ﷺ) praying while he was sitting, and he was reciting a Surah. When he reached the end of it, he would stand up and recite a few verses, then he would bow. I asked him about that, and he said: "I am not like one of you; I do not become weary."