Adam Clarke on Romans 13:5

Ye must needs be subject - Αναγκη, There is a necessity that ye should be subject, not only for wrath, δια την οργην, on account of the punishment which will be inflicted on evil doers, but also for conscience' sake; not only to avoid punishment, but also to preserve a clear conscience. For, as civil government is established in the order of God for the support, defense, and happiness of society, they who transgress its laws, not only expose themselves to the penalties assigned by the statutes, but also to guilt in their own consciences, because they sin against God. Here are two powerful motives to prevent the infraction of the laws and to enforce obedience.

1. The dread of punishment; this weighs with the ungodly.

2. The keeping of a good conscience, which weighs powerfully with every person who fears God. These two motives should be frequently urged both among professors and profane.