Musnad Abu Ya'la al-Mawsili 159:4

Abu Bakr ibn Abi Shaybah narrated to us, Ibn Idris narrated to us, from Rabi'ah ibn 'Uthman, from Muhammad ibn Yahya ibn Habban, from al-A'raj, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The strong believer is better and more beloved to Allah than the weak believer, and in each there is good. Be eager for what benefits you, and seek help from Allah, and do not be incapable. And if something befalls you, do not say: 'If only I had done such and such,' but say: 'Allah has decreed, and what He willed, He did,' for 'if' opens the work of Satan."