How can the Muslim be a trial for the kaafir?
Question

                Allaah says (interpretation of the meaning): 

“Our Lord! Make us not a trial for the disbelievers”

[al-Mumtahanah 60:5]. 

How can a Muslim be a trial for those who disbelieve?.
Praise be to Allah.
    He can be a trial for those who disbelieve if the kuffaar 
    gain power over him, because the kaafir’s gaining power over the Muslim is a 
    trial (fitnah), as they will carry the burden of the sins they commit 
    against us, so that is a trial for them.  

    The phrase “a trial for those who disbelieve” may also 
    be understood as meaning that they try to tempt us away from our religion by 
    means of persecution, as in the verse in which Allaah says (interpretation 
    of the meaning):

    “Verily, those who put into trial the believing men and 
    believing women (by torturing them and burning them), and then do not turn 
    in repentance (to Allaah), then they will have the torment of Hell, and they 
    will have the punishment of the burning Fire”

    [al-Burooj 85:5]. 

    This verse includes both meanings, because the two meanings 
    do not exclude one another. The basic principle in tafseer is that if the 
    verse may be interpreted in two ways that do not exclude one another, then 
    it must be interpreted in both ways. End quote. 

    Shaykh Muhammad ibn ‘Uthaymeen (may Allaah have mercy on him).