Musnad Abu Ya'la al-Mawsili 106:1

Abu Bakr ibn Abi Shaybah narrated to us, Sharik narrated to us, from al-Hasan ibn al-Hakam, from ‘Adi ibn Thabit, from al-Bara’ who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever dwells in the desert becomes harsh."