“The strong believer is better and more beloved to Allah than the weak believer, while there is good in both.”

Abu Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "The strong believer is better and dearer to Allah than the weak believer, and there is good in both. Adhere to whatever brings you benefit, seek the help of Allah, and do not feel helpless. If something befalls you, do not say: 'Had I done such-and-such, it would have been such-and-such;' rather, say: 'Allah has decreed, and whatever He wills, He does.' Indeed, 'if' opens the way before the devil to act."

Narrated by Abu Hurayrah, and the clause quoted is the opening of a longer instruction. What follows tells you what the strength means in practice: pursue what benefits you, seek Allah’s help, and do not give up; and if something goes against you, do not say “if only I had done such and such” — say that Allah decreed it. The praise of strength and the refusal of regret belong to the same hadith.