If you desire to know yourself and to possess yourself, go into yourself and do not search for yourself outside.
Distinguish between what is around you, what belongs to you and yourself! The world surrounds you, your body belongs to you and you are yourself within, made to the image and likeness of God. Return then, transgressor, to your heart within, where you are truly yourself. Outwardly you are an animal, fashioned as the world is fashioned and that is why man is called a microcosm, a miniature world. But inwardly you are made in the image of God and as such are capable of being deified.
Isaac of Stella, Second Sermon for the Feast of All Saints, from Sermons on the Christian Year, Volume One, CF 11, p.14f