Romans 13:9

For this, Thou shalt not commit adultery, thou shalt not kill, Thou shalt not steal, Thou shalt not covet, and if there be any other commandment, it is summed up in this word, namely, Thou shalt love thy neighbor as thyself. Love worketh no to his neighbor: love therefore is the fulfillment of the law.

As noted above, Paul here adhered to the pattern of Jesus' summation of all the Decalogue under the two headings of love to God, and love to people (Matthew 22:34-40; Mark 12:29-31), the latter division being the one considered here. The Christian life is realized, not by an item tabulation of commandments kept or broken, but by a conscious filling of the heart with love toward others, a fulfillment being made possible only by the sacred enthronement within, of the Holy Spirit.

That Paul consciously followed the teachings of the Master throughout is observable in several particulars, as noted by Lenski:

Already in connection with Romans 13:1-7, we noted that Paul is repeating the very teachings of Jesus with regard to government and taxation; he certainly repeats the Master's instructions here, ... has the same order of the commandments as that found in Mark 10:19; Luke 18:20, where the sixth commandment is named before the fifth.[4]

This passage does not teach that if one loves his neighbor he has license to break any of the commandments, but that truly loving one's neighbor will positively restrain from any sinful action against one's neighbor. This is profoundly true and means that the first and uppermost concern of God is that human hearts should indeed overflow with love to mankind, such love making it impossible that specific evil deeds in the social spectrum could be committed.