Mortimer Adler

"Love can be unselfish, in the sense of being benevolent and generous, without being selfless."

"Conjugal love, or the friendship of spouses, can persist even after sexual desires have weakened, withered, and disappeared."

"The love which moves the world, according to common Christian belief, is God's love and the love of God."

"Aristotle uses a mother's love for her child as the prime example of love or friendship."

"Friendship is a very taxing and arduous form of leisure activity."