The subject of government in the Bible is indeed extensive. As we begin, notice that Paul writes that "there is no authority except from God" (verse 1). Though this statement appears in relation to civil authority, God's oversight is broad and deep. Even Satan's authority, as ruler of this world (John 14:30), is assigned by God. Jesus tells Pilate in John 19:11, "You could have no power at all against Me unless it had been given you from above." Those in the church with a position of authority also receive it from God (I Corinthians 12:18, 28). These are important statements on God's overall sovereignty.
In verse 2, Paul mentions "the ordinance of God." God's ordinance states His will, and He clearly establishes civil government. Therefore, we are responsible for obeying civil authority also, for in doing so we are obeying God. These verses do not imply that we must always obey civil government. Other verses show that we must obey it as long as the civil authority does not contradict God's laws. In verses 3-4, Paul comes close to stating that the civil authority somewhat parallels the Old Testament "avenger of blood."
In verses 5-7, God extends our responsibilities to submit to government as a means to keep our consciences clear, as well as to pay taxes, not only so the state can afford to employ these civil servants of God, but also to submit to community customs regarding them and even to give them honor.
These seven verses show three general reasons why humans must be governed. First, law-abiding citizens must be protected. Paul's life was saved in Acts 21:30-32 when Roman soldiers stepped in to save him from the murderous intent of angry Jews. Second, evildoers must be restrained. Third, the general welfare is promoted by helping to establish peace. In I Timothy 2:1-3, Paul commands us to pray that this function is carried out.