John Chrysostom

"And they that resist shall receive to themselves damnation." Then to show the gain of the thing after the fear, he uses reasons too to persuade them as follows:

Homily on Romans 23 ↗

Theophylact of Ohrid

Lest the believers should say: you demean us by subjecting to rulers those who are to receive the Heavenly Kingdom, he shows that he who obeys the authorities obeys God, or, what is far more fearful, he who disobeys the authorities resists God Who established the authorities, and he who resists will be punished both by God and by men. The latter he suggested by saying: "those who resist will bring judgment upon themselves."

Commentary on Romans ↗

Thomas Aquinas

Then when he says, therefore, he who resists, he draws the conclusion. For if the power of rulers is from God and nothing is from God without order, it follows that the order whereby the lower are subjected to the higher powers is from God. Therefore, he who acts against the order and resists the power, resists the ordinance of God: they have not rejected you, but they have rejected me (1 Sam 8:7); he who rejects you rejects me (Luke 10:16). But to resist the divine order is contrary to the good of virtue. …

Commentary on Romans ↗