Daniel 10:12-13

Then he said to me, “Do not be afraid, Daniel, for from the first day that you set your heart on understanding this and on humbling yourself before your God, your words were heard, and I have come in response to your words. But the prince of the kingdom of Persia was standing in opposition to me for twenty-one days. Then, behold, Michael, one of the chief [of the celestial] princes, came to help me, for I had been left there with the kings of Persia.