So also we formerly, under the Law, seemed to do certain things by necessity. But now that we are free, we know that these same things must be done chiefly by love. Love is so beautiful that it stands at the head of the whole Law.
The Apostle also enumerates the goods of love elsewhere, saying: "It does not envy, it does not act improperly" (1 Cor 13:4-5). After indicating many other things in the middle, he ends thus: "It hopes all things, endures all things. Love never fails."
The Savior says in the Gospel that the sign of His disciple is revealed in this, that he loves his neighbor. In my opinion this applies not only to men, but even to angels. The same is said in other words: "Whatever you do not want done to you, do not do to others. And whatever you want men to do to you, do likewise to them" (cf. Mt 7:12).
I do not want my wife to be led into adultery. I do not want my property to be plundered. I do not want false witness to weigh upon me. To embrace everything in one brief saying, I do not want to suffer unjustly anything done to me without deserving it. If, by the love acting in me, I either do not desire the same or do not do it to another, then the whole Law is fulfilled.
It is not difficult to understand how all the commandments, "You shall not kill," "You shall not commit adultery," "You shall not steal," "You shall not bear false witness," and the rest like them, are contained in the fulfillment of the commandment of love.
It is difficult to show how the sacrifices prescribed in Leviticus, abstinence from certain foods and permission to eat others, in which one thing is considered unclean and another clean, and the unbroken yearly cycle of feasts can be reduced to one commandment of love. This can be done only if one passes on to affirm that the Law is spiritual. We served images and examples of heavenly things until the true High Priest appeared. Having once offered Himself in sacrifice, He redeemed us by His blood. Thus the whole truth and difficulty of the former Law was fulfilled in His love for mankind. For the Father so loved the world that He gave His beloved Only-begotten Son for us.
But for the one who already lives in the Spirit, who has put to death the works of the flesh, and who, beloved by the Savior, is no longer called a servant but a friend, the Law is no longer in force. That Law is appointed for sinners, the impious, the disobedient, and the corrupt.
Now, when we have at least in some measure fulfilled everything that was more difficult, we fail to fulfill the one thing that is truly easy, and without which all that we have fulfilled is vain. The body endures the discomforts of fasting. Vigils wear down the flesh. Alms are drawn out with labor. Even if faith is burning, blood in martyrdom is shed with fear and sufferings.
There are some who go through all this. Only love is manifested without suffering. And because it alone makes the heart pure, the devil drives it out of us, so that we may not contemplate God with a pure heart.
For when I sit and speak against my brother, and place a stumbling block before my mother's son (Ps 50:20), when I am tormented by another's happiness and count another's good as evil for myself. Is not what is said in the following words fulfilled in me: "If you bite and devour one another, take heed that you are not consumed by one another"?
Love is a rare possession. Who would wish to be separated from Christ for his brethren, imitating the Apostle? Who, rejoicing with those who rejoice and weeping with those who weep, is struck by another's wound? Who is struck by the death of his brother? We all love ourselves more than God.
See what good things flow from love. If we endure martyrdom in such a way that we desire only that our remains be honored by others, if, following the opinion of the crowd, we fearlessly shed blood and distribute our property until we become poor. Then for such a deed there follows not so much a reward as a punishment, and rather torment for faithlessness than a crown for victory.