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