Imam as-Sa’di said:
The fact that the time in which he 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 seeking refuge with Allah 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 ‘aqeedah, to the point that if it occurred and its occurrence is actualised, 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 this fitnah.
In contrast, if the fear of him were to be removed from the hearts, then the fitnah would be increased when that times comes, And the believers would have no tangible iman to eradicate his fitnah and evil.