The Messenger of Allah ﷺ said, "The strong believer is better and more beloved to Allah than the weak believer, though there is good in both. Strive for what benefits you, seek Allah's help, and do not give up. If something befalls you, do not say, 'If only I had done such and such, things would have turned out differently.' Rather say, 'Allah has decreed, and He does what He wills.' For 'if only' opens the door to the work of Satan."
قال رسول الله ﷺ: المؤمن القوي خير وأحب إلى الله من المؤمن الضعيف، وفي كل خير، احرص على ما ينفعك، واستعن بالله، ولا تعجز، وإن أصابك شيء فلا تقل: لو أني فعلت كان كذا وكذا، ولكن قل: قدر الله وما شاء فعل، فإن لو تفتح عمل الشيطان.