The hugely influential reformer Philip Melanchthon (1497-1560) writes in his commentary on Romans 13:
Meanwhile, the Gospel teaches the godly properly about spiritual and eternal life in order that eternal life may be begun in their hearts. In public it wants our bodies to be engaged in this civil society and to make sure of the common bonds of this society with decisions about properties, contracts, laws, judgments, magistrates, and other things. These external matters do not hinder the knowledge of God from being present in hearts or fear, faith, calling on God, and other virtues. In fact, God put forth these external matters as opportunities in which faith, calling on God, fear of God, patience, and love might be exercised.
There is a certain wisdom worthy for a Christian to know. God cast the church into the midst of these occupations because he wants to become known among men in a common society. He wanted all offices of society to be exercises in confession, and at the same time exercises of our faith and love.
Wise words on justice and the social and political implications of the Gospel from the reformer whose impact is still felt today, 450 years after his death.