Love works no ill to his neighbor: therefore love is the fulfilling of the law.
All Commentaries on Romans 13:10 Go To Romans 13
Ambrosiaster
AD 400
Paul is using the words of the law to arrive at the meaning of the gospel. Therefore when he records the fulfilling of the law he ties it to the gospel, demonstrating that both have a single author. Yet in the time of Christ it was necessary to add something, viz., that we should love our enemies as well as our neighbors…. What does it mean to love an enemy, except to choose not to hate him any longer and to seek to do him no harm? … For the Lord himself on the cross prayed for his enemies in order to demonstrate what the fullness of righteousness, which he had taught, actually was. Commentary on Paul’s Epistles.