Musnad Abu Ya'la al-Mawsili 6:92

Abu Khaythama narrated to us, Jarir ibn Abd al-Hamid narrated to us, from al-Mughira, from a man from Banu Amir, Mus'ab ibn Sa'd narrated to us, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I am more afraid for you of the trial of ease than I am of the trial of hardship. You were tested with the trial of hardship and you were patient. And indeed, the world is green and sweet."