" To the objection that Christian love is extended to all people but friendship involves mutuality, Aquinas says that when we love a friend, we love everything about that friend. Thus our love will want to expand to include the friends of our friend, even if those friends have no other connection to us. 'When a man has friendship for a certain person, for his sake he loves all belonging to him, be they children, servants, or connected with him in any way. Indeed, so much do we love our friends, that for their sake we love all who belong to them, even if they hurt or hate us.' So when we love God, we also love those whom God loves. Each human being is, potentially, a friend of God. So whenever one human being, a friend of God, is loving God, that love is naturally extended to all the other friends of God--that is, to all other people insofar as they are also friends or potential friends of God. This is why we love our enemies: they too belong to God in that God's love extends to his enemies also. "
― , Friendship: The Heart of Being Human