When looking through a glass darkly, you can see refracted images of what somebody truly looks like. You see a shadow of reality. When the image is very clear this resonates with your spirit and you feel a kindred, homely, warm feeling.
This is one reason why people fall in love.
This can only happen by seeing the spirit of a person, not their bodily image. It is true that the eyes give a penetrating glance into the soul, but one must keep in mind this is only a refracted image of the inner flame, not the spirit itself.
I've noticed most people have a murky image due to a sleepy or comatose spirit. A person who is intimate with God has a certain intensity of being-a radiant countenance-that attracts people due in part to the Natural Law. All people see this radiance intuitively, even if they cannot articulate why. As things come to a point, this line of demarcation will become more manifest. The Good will keep getting better and the Bad will increase their dullness of bearing. When logic, persuasive arguments, and even the Bible fail to attract people to God, and people become more animal-like and grow feral, their instincts will be relied on more and more. Then they will be drawn to the radiant ones.
I think this plan has already been written down in a book somewhere.