He who loves Me, says the Lord, will keep My commandments; and "this is My commandment, that you love one another". Thus he who does not love his neighbor fails to keep the commandment and cannot love the Lord. Blessed is who who can love all men equally. (Maximos the Confessor)

Both of the commandments are from the Gospel of John. In each Jesus is quoted using the Greek agape.

Greek distinguishes between eros or physical love, philia or the love of friends, and agape or a love that is beyond sexual or friendly.

Aramaic, the language in which Jesus was almost certainly speaking, rakhma and khuba are two forms of love, the first unconditional and the second reciprocal.

The Hebrew Scriptures, and especially the book of Isaiah, often refer to racham as God's compassion or mercy. In Isaiah 54:10 we read, "'For the mountains may be removed and the hills may shake, But My lovingkindness will not be removed from you, And My covenant of peace will not be shaken,' Says the Lord who has compassion on you."

I don't know about Maximos, but I perceive that Jesus was referring to a relationship where we self-identify with the other, we love our neighbor as our self.