The Fitnah of the Dajjal and Gog and Magog
Imām as-Sa’dī said:
The fact that the time in which he will come is unknown indicates that no believer can guarantee safety for himself from encountering that time. This is an affair which is possible, and its evil and fitnah are to be feared. The need of the slave for having protection from his fitnah by all means is something known. And from the greatest means is seeking refuge with Allāh from him. Also, this is through supplication and fearing his fitnah. Thus, it is inevitable that one does so in all levels of this ummah.
This is a firmly placed ‘aqīdah, to the point that if it occurred and its occurrence is actualized, then this ummah—specifically those who have a connection to the correct and sound belief system—will be able to defend itself from this evil and be protected from his fitnah.
In contrast, if the fear of him were to be removed from the hearts, then the fitnah would be increased when that time comes. And the believers would have no tangible īmān to eradicate his fitnah and evil.