It’s simple: compassion is a doorway to love.
Arthur Schopenhaur sought to define compassion in his work On the Basis of Morality, and in that work he proposed, and I’m summarizing here, that compassion comes from seeing oneself in another, feeling another’s pain, and essentially removing the distinction between self and other, at least in terms of emotion. When one person shares in another’s woe, one is compelled to help alleviate that woe. Thus the shared suffering (empathy) leads to a desire and an action to end it (compassion). Many Buddhists see compassion as the ideal action in any and every situation. Though I don’t call myself a Buddhist at the moment, I agree with that ideal, and I believe there isn’t a problem in the world that can’t be solved through people working together in compassion.
So how is compassion a doorway to love? Using Schopenhaur’s model, if one continues breaking down the barrier between self and other, one begins to see all life as connected. When this happens, one can feel a desire to alleviate all of the suffering in life: ultimate compassion. A drive to, as Schopenhaur would put it, “Harm no one; on the contrary, help everyone as much as possible.” And this is but one step short of what I see as ultimate love: the action of not only attempting to alleviate all suffering, but of then going further and helping to create abundant joy anywhere and everywhere one goes.
As compassion spreads, more and more people will come to the doorway of love, and more and more people will pass through it.