Loves that we had supposed to have no importance but for ourselves--love between husband and wife, parents and children, sisters and brothers, the love of friends--all these natural loves, if we love with Christ's heart, increase the life of the world, and build up the kingdom of heaven here on earth. That harder love to achieve, the love of our enemies, of those who hate us and persecute us, does not merely bring us pardon in our own sins, but is redemptive; it has a reach as wide as the cross, and not only brings mercy to those who are its object, but to the whole world.
Everyone who lives the Christ-life, and therefore loves with the heart of Christ, is adding to the divine love in the world, which is the only force opposed to hate. Whether they love their betrothed, their wife, or children, or their enemy, whether their love is happy and fulfilled or is one that they must forego and seem to frustrate, they are adding to the sum total of love that is redeeming the world.
via Light on Dark Water