Musannaf Ibn Abi Shayba 27:592

Muhammad ibn Abi Ubaydah narrated to us, he said: My father narrated to us, from al-A’mash, from al-‘Ala’ ibn Badr, from Tamim ibn Hudhlum, who said: I have sat with the companions of Muhammad, may Allah bless him and grant him peace, and with Abu Bakr and Umar. I have not seen anyone more ascetic regarding the world, nor more desirous of the Hereafter, nor anyone whom I would love more to be in his skin on the Day of Resurrection, than you, O Abdullah ibn Mas’ud.