These words conclude a large section of the Letter to the Romans in which Saint Paul presents the Christian life as a life of love for our brothers and sisters. This is, in fact, the new spiritual practice that Christians are called to offer to God under the guidance of the Holy Spirit (see Rom 12:1), who first brings it to life in their hearts.
Summing up the content of this section, the apostle states that loving our neighbor enables us to do the will of God, contained in the Law (that is, in his commandments), and to do it fully and perfectly. Loving our brothers and sisters is the most beautiful, most authentic way of showing our love for God.

“Love is the fulfillment of the law”

But what does this fullness and perfection consist of concretely? One can gather it from the verses that follow, in which the apostle describes the different expressions and effects of this love.
First of all, real love does no harm to one’s neighbor (see Rom 13:10). It makes us live all of God’s commandments, without excluding any (see Rom 13:9), since their first objective is to help us avoid every kind of evil we could possibly fall into—every evil against ourselves or our brothers and sisters.
Besides not doing any evil, this love urges us to do all the good that our neighbors may need (see Rom 12:6-8).
This Word encourages us to have a love that is concrete and sensitive to the needs, hopes, and legitimate rights of our brothers and sisters. It is a love that is respectful of human and Christian dignity, a love that is pure, understanding, able to share, open to all—as Jesus has taught us.
This love is not possible unless we are willing to step out of our individualistic and self-sufficient ways. Therefore, this Word helps us to overcome those egotistical tendencies (pride, greed, lust, ambition, vanity, etc.) that we carry within us and that can be our major stumbling blocks (see Rom 12:9-21).

“Love is the fulfillment of the law”

How then can we live the Word of Life during this month of Christmas? By keeping in mind the various demands of loving our neighbor that this Word calls us to fulfill.
In the first place, we will avoid doing every kind of evil against our neighbor. We will pay close attention to the commandments of God that relate to our vocation, to our professional life, and to the environment in which we live. The first condition to live out Christian love is never to go against the commandments of God.
In addition, we will pay attention to what constitutes the very soul, reason and aim of all the commandments. Each one of them, as we have seen, wants to nurture in us a love that is ever more vigilant, more delicate and respectful, ever more concrete towards our neighbors.
At the same time, we will grow in being detached from ourselves, in overcoming our egoism; this will come as a consequence of living Christian love.
This is how we will do the will of God “fully”; we will show him our love in the way that is most pleasing to him (see Rom 12:2).

“Love is the fulfillment of the law”

This was the experience lived by a lawyer who works for his city’s Department of Labor. “One day, I presented the owner of a company with a claim that his employees had not been paid according to the prescribed regulation,” he stated. “After fourteen days of intense research, I found the documents that proved that he was not fully respecting the labor laws. I asked Jesus to give me the strength to remain faithful to his words that called for me to be truthful and, at the same time, to be an instrument of his love.
“When the owner was confronted with the proof, he defended himself by saying that certain laws seemed unjust to him and to others. I affirmed that our mistakes could not be justified by the behavior of others who do not comply with the rules. During the conversation that followed, I realized that he had the same desire for justice and equality that I had, but he had let himself be influenced by those around him.
“In the end he said to me, ‘You could have humiliated and crushed me, but you didn’t do that. Because of this, I realize I have a moral duty to right this wrong.’ He, however, had a pressing appointment and could not wait for me to write up my report of his infraction. He took a blank piece of paper and signed it. This proved to me that he was ready to make an immediate change.”
        

Chiara Lubich