Musnad Ahmad 1153:115

Sufyan narrated to us, from Ibn ‘Ajlan, from Sa‘id, from Abu Salamah, from ‘Aishah: "We had a mat that we would spread out during the day and partition off at night." Something was obscure to me that I did not understand from Sufyan, that the Messenger of Allah (ﷺ) [said]: "The Muslims pray with his prayer." He then said: "Take upon yourselves of the deeds what you can endure, for Allah, the Almighty and Majestic, does not grow weary until you grow weary. And when he performed a prayer, he would make it constant, and the most beloved of deeds to him was that which was most consistent."