The Quran

ما أَصابَ مِن مُصيبَةٍ فِي الأَرضِ وَلا في أَنفُسِكُم إِلّا في كِتابٍ مِن قَبلِ أَن نَبرَأَها ۚ إِنَّ ذٰلِكَ عَلَى اللَّهِ يَسيرٌ

Ali Unal

No affliction occurs on the earth (such as droughts, famines, or earthquakes), or in your own persons (such as diseases, damages to your property, or the loss of loved ones), but it is recorded in a Book before We bring it into existence – doing so is surely easy for God –¹

That is, recording such acts out of His Eternal Knowledge and keeping them recorded, and then bringing them into existence by His Power for many wise purposes – such as to punish the sinful as they deserve, or to warn them against their end, or to forgive the sins of believers, or to promote the sinless to higher ranks – is absolutely easy for God.
The verse also includes a consolation for people in affliction. Provided the intended lesson has been learned, when we consider any misfortune in the light of Divine Destiny, or as an application of Divine Destiny, we may find rest and not feel the need to complain about it. The verse to come corroborates this.