Musannaf Ibn Abi Shayba 33:718

Jarir narrated to us, from Mansur, from Ibrahim, from Amr ibn Maymun, who said: A peg used to be driven into the wall of the mosque for him. When he grew weary of standing in prayer and it became difficult for him, he would take hold of the peg to lean upon it, or a rope would be tied for him, and he would hold onto it.