Musannaf Ibn Abi Shayba 33:4

'Abbad ibn al-'Awwam narrated to us, from al-'Ala' ibn al-Musayyab, from a man who narrated to him, he said: The disciples said to 'Isa ibn Maryam, "What do you eat?" He said, "Barley bread." They said, "And what do you wear?" He said, "Wool." They said, "And what do you use as a bed?" He said, "The earth." They said, "All of this is difficult." He said, "You will not attain the kingdom of the heavens until you endure this with pleasure," or he said, "with desire."