John 16:33b: . . .. In the world ye shall have tribulation: but be of good cheer; I have overcome the world.
J. R. Miller:
Tribulation is God*s threshing . . . not to destroy us, but to get what is good, heavenly, and spiritual in us separated from what is wrong, earthly, and fleshly. Nothing less than blows of pain will do this. The evil clings so to the good, the golden wheat of goodness is so wrapped up in the strong chaff of the old life that only the heavy flail of suffering can produce the separation.