Render therefore to all their dues: tribute to whom tribute is due; custom to whom custom; fear to whom fear; honor to whom honor.
Read Chapter 13
Ambrosiaster
AD 400
Giving honor to the powers that be in this world may have the effect that, if they see the humility of Christ’s servants, they may praise rather than curse the gospel’s teaching. Commentary on Paul’s Epistles.
Also to the Romans: "Render to all what is due: tribute to whom tribute is due, custom to whom custom, fear to whom fear, honour to whom honour; owe no man anything, except to love another."
Paul urges the people to give their rulers not only money but honor and fear as well. Fear in this context means very great honor, not the kind of fear which comes from a bad conscience.
So far as concerns the honors due to king or emperor, we have a clear ruling to be subject in all obedience, according to the apostle’s command, to magistrates and princes and those in authority, but within the limits of Christian discipline, i.e., so long as we keep ourselves free of idolatry.