Here's something I wrote on this some years ago.
THE GREATEST VIRTUE
If we were to ask "what is the greatest Christian virtue" many would say "it is faith." But faith is not the greatest Christian virtue. As Paul informs us in 1 Cor 13:2, "If I have all faith so as to move mountains but do not have love I am nothing." So much for sola fide unqualified. Paul is pretty blunt about it. If you don't love, you are nothing, and your life counts for nothing but wasted space.
It is often said that there are four Greek words for love. In a sense this is true; in a sense it is a misunderstanding. The four words are: eros (desire/physical love), storge (familial love), philia (fondness), and agapan. Agapan originally was just a synonym for philia in Classical Greek -nothing more. In ancient Greece, the birthplace of philosophy, the entire concept of agape as we understand it remained yet unborn and un-thought of...
Jesus and the NT authors had a concept so bold, so revolutionary, so far beyond what the great sages and philosophers had that they invented a new name for it: agape, as a noun -well, almost. Very rarely in Classical Greek the noun was used, but it never meant anything beyond philia until Jesus of Nazareth emerged on the scene. To understand how remarkably revolutionary this concept was, we can compare it to the highest form of love known to the pagan Greeks: philia.
As I said, philia is fondness. It is warmth, intimacy. It can refer to physical love; the verb philein can men to caress or kiss, but even then philia is more than merely physical. Philia IS beautiful. But it is conditional. Aristotle wrote that only those who have attractive qualities can expect to be loved. He said that of people who desire to be loved but have no outstanding qualities, that they are being ridiculous. Aristotle insisted that no one can expect to be loved "if there is nothing in him to arouse affection." Plato said it most succinctly: "love is for the lovely."
By contrast, Christian love is an obligation and ability to love the unlovely. The leprous, the prisoner, the sinner, the beggar, the homeless, the tax-gatherers, the enemy.
Aristotle also said love cannot be widely diffused. The circle of friendship must be narrow. Christian love is the opposite. It is all embracing. Augustine said God loves all of us as if we were the only one. Philia is a reaction of the heart -it happens effortlessly. But mere sentimentality is love's counterfeit. Agape can involve the heart, but it requires the whole personality. It requires in addition, the will: it can embrace even a hated enemy. At such times it can be more a conquest than sentimentality which involves a victory over the self. Eph 3:19 says it passes knowledge. If this sounds lofty and abstract it is not. It is simple and concrete, but still profound. We truly embrace it not through scholarship, but daily, listening closely as a child must learn:
Mk 10:15 says "Truly I say to you, whoever does not receive the Kingdom of God like a child shall not enter at all."
Prayer: Jesus Christ, Son of God, have mercy on us, sinners. Help us to bring love into our loveless world. Without love we are nothing and our lives count for nothing.