C.S. Lewis's famous work on the nature of love divides love into four categories: Affection, Friendship, Eros and Charity. The first three are loves which come naturally to the human race. Charity, however, the Gift-love of God, is divine in its source and expression, and without the sweetening grace of this supernatural love, the natural loves become distorted and even dangerous.
C. S. Lewis Signature Classic: The Four Loves