
Nabi (sallallahu ‘alayhi wasallam) said in an authentic Hadith:
بادروا بالأعمال فتنا كقطع الليل المظلم
‘Rush towards good deeds before a time comes wherein there will be such fitnahs that will be like the portions of a dark night.’ (Sahih Muslim)
Here is a talk that I delivered expounding on this Hadith, listen here