قَدَرُ اللَّهِ وَمَا شَاءَ فَعَلَ

Qadarullaahi wa maa shaa'a fa'al

It is the Decree of Allah and He does whatever He wills. Abu Huraira (RA) reported Allah's Messenger (ﷺ) as saying: A strong believer is better and is more lovable to Allah than a weak believer, and there is good in everyone, (but) cherish that which gives you benefit (in the Hereafter) and seek help from Allah and do not lose heart, and if anything (in the form of trouble) comes to you, don't say: If I had not done that, it would not have happened so and so, but say: (The dua is mentioned above) and your" if" opens the (gate) for the Satan.

Reference: Muslim: 2664