Abu Dawud Book 2, Hadith Number 948.

Narated By Umm Qays bint Mihsan : Hilal ibn Yasaf said: I came to ar-Raqqah (a place in Syria). One of my companions said to me: Do you want to see any of the Companions of the Prophet (PBUH)? I said: A good opportunity. So we went to Wabisah.

I said to my friend: Let us first see his mode of living. He had a cap with two ears stuck (to his head), and wearing a brown silken robe. He was resting on a staff during prayer. We asked him (about resting on the staff) after salutation; He said: Umm Qays daughter of Mihsan said to me that when the Apostle of Allah (PBUH) became aged and the flesh grew increasingly on him, he took a prop at his place of prayer and rested on it.