Yet let us consider what the same Apostle says: “Love is the fulfillment of the law” (Rom 13:10).
Therefore, where love is, what can be lacking? And where it is not, what can be of use?
The demon also believes, but he has no love. Cf. Jas 2:19.
No one has love unless he believes.
One who has no love may, indeed, hope for forgiveness, but he hopes in vain.
Yet one who has love cannot lose hope.
Therefore, where love is, faith and hope are necessarily present.
Where there is love for neighbor, there is necessarily also love for God.
For if a man does not love God, how can he love his neighbor as himself, when he does not love even himself?
Such a man is certainly impious and unjust. And one who loves iniquity surely does not love his own soul, but hates it. Cf. Ps 10:5.
Let us hold fast, then, to the Lord’s commandment: let us love one another.
Then we shall fulfill everything else that is commanded, because love includes everything else.
Whether He said “precept” (praeceptum) or “command” (mandatum), both are translations of one Greek word, namely ἐντολή.
He had already expressed this judgment before, and you should remember that I explained it to you as far as I could.
Indeed, in that place He said: “A new commandment I give to you, that you love one another. As I have loved you, so you also love one another” (Jn 13:34).
And now that commandment is repeated.
Only there He said: “A new commandment I give to you.” Here He says: “This is My commandment.”
There He spoke as though there had not previously been such a commandment. Here He speaks as though there should be no other commandment of His.
But there it was called “new” so that we would not remain in our former state.
Here it is called “Mine” so that we would not think it could be neglected.
But what, brethren, should we think concerning what He says here: “This is My commandment,” as though there should be no other?
Is the commandment of that love by which we love one another the only one He has?
Is there no greater commandment, namely that we should love God?
Or has God given us only the commandment of love, so that we should seek no other?
But the Apostle points to three commandments when he says: “And now these three abide: faith, hope, love; but the greatest of these is love” (1 Cor 13:13).
And if those two commandments are contained in love, that is, in charity, nevertheless it is called greater, not the only one.
See, then, how many commandments have been given us concerning faith, and how many concerning hope.
Who can gather them into one? Who can number them?
But let us consider what the Apostle said: “Love is the fulfillment of the law” (Rom 13:10).
Therefore, where love is present, is anything still needed?
And where love is absent, what else can help?
The demon believes, cf. Jas 2:19, but does not love.
No one loves who does not believe.
In vain, certainly, yet nevertheless, one who does not love may hope for mercy.
But one who loves cannot remain without hope.
Thus, where love is present, faith and hope are inevitably present also.
And where love for neighbor is present, love for God is inevitably present.
For one who does not love God, how can he love his neighbor as himself, since he does not love even himself?
Such a man is certainly impious and unrighteous, for he loves iniquity. Not openly loving, but “hating his own soul” (cf. Ps 10:5).
So let us hold fast to this commandment of the Lord, that we love one another.
And let us also fulfill everything else that He commands, because everything else is held by us in this commandment.
Certainly, this love for neighbor differs from the love by which men love one another merely as men.
And so that this distinction may be clear, He added: “as I have loved you.”
For why did Christ love us, if not so that we might reign together with Christ?
So let us love one another for this reason, in order to distinguish this love from the love of other men.
They love one another not for this reason; in fact, they do not love at all.
But those who love one another for the sake of attaining God truly love one another.
And in order to love one another, they love God.
Such love is not present in all men. Therefore only a few love with the aim that God may be all in all (1 Cor 15:28).