We will be shaken

In the story of Simon Peter, he was shaken and humbled so much that his natural confidence turned to dependence on God. When we are shaken, what isn't of Jesus falls away, and that's why Jesus lets trials happen. John Bevere explains this on p. 89 of "The Bait of Satan":

Trials in this life will expose what is in your heart -- whether the offense is toward God or others. Tests either make you bitter toward God and your peers or stronger. If you pass the test, your roots will shoot down deeper, stabilizing you and your future. If you fail, you become offended, which can lead to defilement with bitterness.

I'm curious about how to discern which trials are just spiritual attacks by Satan and his evil spirits versus trials that are put in our lives to strengthen our faith in Jesus. Or are they one in the same?