Toward the end of a long day of slogging through commentaries, I came across this gem from Emil Brunner’s Letter to the Romans, at 13:8:

“To owe no one anything–that is the principle of justice.  ‘To everyone his own.’ With that Paul concludes his remarks regarding the attitude of the Christian to the authorities.  Yet this ‘owing no one anything’ is not separate and independent, but is embedded in something still greater.  Whoever owes nothing to anyone parts from the other once he has done his duty.  Love is greater than justice; it does more than justice demands.  The demand of justice ends with the individual; love alone is all-embracing because it does not keep its eye on ‘something’ that one owes to the other but on the other himself and myself.  I owe myself to him and therefore I am never done with him…  

“The commandments [in the Law] always mean the one thing: Love.  That which in the Law is expressed in isolated demands proves to be united from the point of view of faith in Jesus Christ and the love revealed in him.  So long as we stand ‘under the Law’ we cannot perceive this hidden unity of all the commandments.  It is part of legalism that the will of God must appear to it as a multiplicity of commandments.  In actual fact it is one and indivisible; God wants nothing else except love because he himself is love.  God’s commandments, rightly understood, always declare one thing only: love your neighbor.  There are individual examples as to what this love will mean in individual cases–just as the Lord in the Sermon on the Mount expounded the commandments as commandments of love. As God in Jesus Christ gives and wills himself entirely to us so we, too, ought to give ourselves entirely to our neighbor, entirely embrace him with our love.  If we do that, then there is no further need of any law; then everything that the law demands has been done.”