Acts 12:21-23:

And upon a set day Herod, arrayed in royal apparel, sat upon his throne, and made an oration unto them.
And the people gave a shout, saying, It is the voice of a god, and not of a man.
And immediately the angel of the Lord smote him, because he gave not God the glory: and he was eaten of worms, and gave up the ghost.

Notes on Acts 12:21-23:

For those who believe that God would NEVER make anyone sick, this verse presents a serious problem.  It was the angel of the Lord who smote Herod with a fatal illness, not an evil spirit from the devil.  Even in the New Covenant, God can judge serious sin (in this case, trying to steal glory that rightfully belongs only to God).  God has not hired out His judgment to the devil.  He says that vengeance is HIS (Romans 12:19), so He does not send the devil to take vengeance upon people.

See also:

Notes on Psalm 78:49-51
Notes on 1 Samuel 16:14-23
YOU Can Do Miracles
Sickness as Chastening and Judgment in the New Testament
Did God PUT Sicknesses on Old Testament People in the Old Testament or ALLOW the Devil to Do It?
Condition: Worms