When Paul says love does no harm to a neighbor, he means genuine love refuses to use people, injure them, or treat God's commands as optional. Love fulfills the law because it seeks the neighbor's good before God.
Romans 13:8-10 follows Paul's teaching about public responsibility. He then gathers several commandments under the command to love your neighbor as yourself.
The passage prevents love from becoming vague. In Romans, love has moral shape and concrete concern for another person.
should not use love to erase truth or use truth to excuse harm. Paul keeps love and God's moral will together.