Musnad Abu Ya'la al-Mawsili 160:1

Ubayd Allah ibn Umar al-Qawariri narrated to me, Ubayd ibn Waqid al-Laythi narrated to us, Sa'id ibn Atiyyah narrated to us, from Shahr ibn Hawshab, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever is pleased that Allah should answer him during hardships and distress, let him increase supplication during times of ease."