Daniel 10:13; Daniel 10:20

13 "But the prince of the kingdom of Persia was withstanding me for twenty-one days; then behold, Michael, one of the chief princes, came to help me, for I had been left there with the kings of Persia.
20 Then he said, "Do you understand why I came to you? But I shall now return to fight against the prince of Persia; so I am going forth, and behold, the prince of Greece is about to come.