Then said he, Knowest thou wherefore I come unto thee? and now will I return to fight with the prince of Persia: and when I am gone forth, lo, the prince of Grecia shall come. Knowest thou wherefore I come - So high art thou in the favor of God, that he hath sent me unto thee to give thee farther satisfaction; though I was elsewhere employed upon a most important mission, and I must speedily return to accomplish it, viz.: -
To fight with the king of Persia - To remove all the scruples of Cyrus, and to excite him to do all that God designs him to do for the restoration of my people, and the rebuilding of the city and temple of Jerusalem. Nothing less than a supernatural agency in the mind of Cyrus can account for his decree in favor of the Jews. He had no natural, no political inclination to it; and his reluctance to obey the heavenly motions is here represented as a fight between him and the angel.
The prince of Grecia shall come - I believe this refers to Alexander the Great, who was to destroy the Persian empire. See Daniel 11:2-3 (note).