2 Corinthians 11:14

11:14 And no wonder, for even Satan disguises himself as an angel of light.

2 Corinthians 12:7

12:7 even because of the extraordinary character of the revelations. Therefore, so that I would not become arrogant, a thorn in the flesh was given to me, a messenger of Satan to trouble me – so that I would not become arrogant.