Adam Clarke's Commentary on the Bible

Verse 13 (Daniel 10:13)

But the prince of the kingdom of Persia withstood me - I think it would go far to make a legend or a precarious tale of this important place to endeavor to maintain that either a good or evil Angel Is intended here. Cyrus alone was the prince of Persia, and God had destined him to be the deliverer of his people; but there were some matters, of which we are not informed, that caused him to hesitate for some time. Fearing, probably, the greatness of the work, and not being fully satisfied of his ability to execute it, he therefore for a time resisted the secret inspirations which God had sent him. The opposition might be in reference to the building of the temple.

But lo, Michael - Gabriel, who speaks, did not leave Cyrus till Michael came to take his place. Michael, he who is like God, sometimes appears to signify the Messiah, at other times the highest or chief archangel. Indeed there is no archangel mentioned in the whole Scripture but this one. See Judges 1:9 ; Revelation 12:7 .

- Adam Clarke's Commentary on the Bible