Musannaf Ibn Abi Shayba 3:2543

Waki’ narrated to us, he said: Isma’il bin Abi Khalid narrated to us, from ‘Amr al-Shaybani, he said: I saw Ibn Mas’ud becoming drowsy in the mosque at night, so he would not leave any person in the mosque except that he would expel him, except for a man who was praying.