וְשַׂ֣ר ׀ מַלְכ֣וּת פָּרַ֗ס עֹמֵ֤ד לְנֶגְדִּי֙ עֶשְׂרִ֣ים וְאֶחָ֣ד י֔וֹם וְהִנֵּ֣ה מִֽיכָאֵ֗ל אַחַ֛ד הַשָּׂרִ֥ים הָרִאשֹׁנִ֖ים בָּ֣א לְעָזְרֵ֑נִי וַאֲנִי֙ נוֹתַ֣רְתִּי שָׁ֔ם אֵ֖צֶל מַלְכֵ֥י פָרָֽס׃
But the prince of the kingdom of Persia withstood me one and twenty days; but, lo, Michael, one of the chief princes, came to help me; and I was left over there beside the kings of Persia.
Rashi on Daniel
has been standing against me to battle with me in heaven by requesting an extension for the kingdom for Persia to enable them to subjugate you (Israel). Behold twenty-one days that he has been standing against me.
Rashi on Daniel
the first princes those counted first among those who enter.
Rashi on Daniel
and I remained there to silence the princes of Persia in heaven.