Musannaf Ibn Abi Shayba 33:16

'Abd al-Salam ibn Harb narrated to us, from Khalaf ibn Hawshab, who said: 'Isa ibn Maryam (Jesus, son of Mary) said to the disciples: "O salt of the earth, do not become corrupt, for if a thing becomes corrupt, nothing can rectify it except salt. And know that there are two traits in you: laughter without wonder, and sleeping in the morning without having stayed up at night."