Charity
Lewis points out that earthly loves are not enough in themselves. There is something else necessary is required. It is hard to describe, but in the end it is related to the whole Christian life.
There is a rivalry between our natural loves and the love of God. Augustine says that we shouldn't let our happiness depend on something we can lose. Lewis disagrees and points out that Jesus suffered heartbreak on earth. "Love anything and your heart will certainly be wrung and possibly be broken." "The only place outside Heaven where you can be perfectly safe from all the dangers and perturbations of love is Hell." The real question about loving God and the rivalry with other loves is which do you serve when the alliterative comes, God or the earthly love.
How does all of this relate to how God loves. God is love. That is the beginning. Love is the divine energy. The primal love of God is a Gift-love. God had no need to create. He did it out of love.
As the creator, God put Gift-loves and Need-loves in us. And, he gives us a share of his own Gift-love. Lewis cautions that it is easy to slip into the thought that God loves us because we are intrinsically lovable. That is a big mistake.
He ends with a discussion of how we will relate to our beloveds in heaven.