When Jesus went into the room where the elderly lady lay, Luke writes, "He stood over her and rebukedher fever," another detail Matthew and Mark omit. Was he addressing some hostile power? On another occasion, He rebuked the raging wind and water to end a storm on the Sea of Galilee (Luke 8:24). "Rebuked" in this verse is the same word used in Luke 4:35 and Mark 1:25, where Jesus "rebuked" the demon during the exorcism in the synagogue. The word means "to censure or admonish." When Jesus rebuked something, evil was present, and His example instructs us that evil must be condemned if real healing is to occur.
There are times when the solutions to our problems may require rebuke or strong admonition. No one enjoys being on the receiving end of a rebuke, yet if sin has caused the problem, it must be rebuked before repentance can happen. In a larger sense, the world desires peace, but few are willing to punish evil. The attitude toward evil today is not that of condemnation but of toleration.
Even so, not all sickness is caused by sin (John 11:4). At times, God permits sickness to provide an opportunity to bring glory to Himself and His Son.
— Martin G. Collins