In the English language, we have one word that signifies love, the Greek, the language of the NT, has four. Not all the words are used in the NT. The main two are phileo and agape.
The other two are eros which refers to sexual love, and storge, which is love between kinfolk.
Phileo refers to love between friends, a close friendship, fondness, affection, liking. Agape is a higher love, compassion, to do with the moral principle of loving, and is born out in love of the undeserving, loving without reward, loving though rejected. It is of course the way God loves us. This word, agape is the one used most often in the NT.
This is the word used in John 3:16“For God so loved the world,i that he gave his only Son, that whoever believes in him should not perish but have eternal life. And interestingly both phileo and agape are used in the exchange between Jesus and Peter, after the resurrection, in John 21: 15When they had finished breakfast, Jesus said to Simon Peter, “Simon, son of John, do you love me more than these?” He said to him, “Yes, Lord; you know that I love you.” He said to him, “Feed my lambs.” 16He said to him a second time, “Simon, son of John, do you love me?” He said to him, “Yes, Lord; you know that I love you.” He said to him, “Tend my sheep.” 17He said to him the third time, “Simon, son of John, do you love me?” Peter was grieved because he said to him the third time, “Do you love me?” and he said to him, “Lord, you know everything; you know that I love you.” Jesus said to him, “Feed my sheep.”
God is love. His love for us goes to depths we can not even imagine. He created us, knowing full well, that our first parents would make a mess of things and sin would enter this world. And His love for us goes to such depths that He allowed His Son to die in our place so that we, though sinful, wretched creatures, may be His adopted sons and daughters. This plan for our salvation was made before the creation of the world. And in the fullness of time, God sent His only begotten Son to live on this earth, leaving the glories of heaven for a life as a human, to fulfil the plan.
He lived a sinless life, obeying His Father in all things, (John 12: 49For I have not spoken on my own authority, but the Father who sent me has himself given me a commandment—what to say and what to speak.) teaching and healing and reaching out to sinners.
The Father, in several places in the NT called Jesus His Beloved Son. One such place was the Transfiguration, when He added, Listen to Him! Luke 9: 35And a voice came out of the cloud, saying, “This is my Son, my Chosen One;c listen to him!”
During His ministry, He was asked what was the greatest commandment. He answered: Matt 22: 37And he said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind. 38This is the great and first commandment. 39And a second is like it: You shall love your neighbor as yourself.
God loves us, Jesus commands us to return that love, and to love our neighbour as ourself. Several other times Jesus tells us to love our enemies, to care for the unfortunate, and the ultimate comes with the NEW commandment. Nothing like this is found in the OT. John 13: 34A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another. 35By this all people will know that you are my disciples, if you have love for one another.” Not only is this love self sacrificial, but it is the sign that you are His disciple.
So, agape originates with the Father, and is freely given to us by the death of His Son, so that we can have eternal life, and spend eternity with Him. And because of that love He gives us, we return His love by loving Him, and spreading it to our neighbour, our enemy, the unfortunate, and each other. This also gives a witness to others that we belong to Him, and if necessary, we will die for Him. What greater witness is this? The Greek word for witness is the word we get martyr from.
The saying is that love makes the world go round. But this love not only goes round, as in returns to God, it reaches out to others, as Christ reached out to sinners, and as He reached out to us.
1 Cor 13: 8Love never ends. As for prophecies, they will pass away; as for tongues, they will cease; as for knowledge, it will pass away. 9For we know in part and we prophesy in part, 10but when the perfect comes, the partial will pass away. 11When I was a child, I spoke like a child, I thought like a child, I reasoned like a child. When I became a man, I gave up childish ways. 12For now we see in a mirror dimly, but then face to face. Now I know in part; then I shall know fully, even as I have been fully known.
13So now faith, hope, and love abide, these three; but the greatest of these is love.
Agape, the love of God.