In the name of Allah, Most Gracious, Most Merciful.
Narrated Abu-Huraira (May Allah be satisfied with him): Allah’s Messenger (May Allah exalt his mention and protect him from imperfection) said: “The strong believer is better and dearer to Allah than the weak believer, and all of them have goodness. Be keen on what benefits you and seek help in Allah, and do not give up. If anything afflicts you do not say: “If I had done such and such thing, such and such would have happened,” but say: “Allah decrees, and what Allah wills comes to pass.” For, (the utterance) “If I had done such and such,” provides an opening for Satan to creep stealthily.” (Muslim)
Riyaadiss-Saliheen (The Meadows of the Righteous) (Abridged)
By Imam An Nawawi Vol. (1)
Publisher: Dar Al-Manarah
Chapiter 11, Page 197, Number 76