Matthew 16:22-23:

Then Peter took him, and began to rebuke him, saying, Be it far from thee, Lord: this shall not be unto thee.
But he turned, and said unto Peter, Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men.

See also:

What’s RIGHT with You?
Can a Christian Have a Demon?