It is possible to contemplate God not only outside us and within us, but also above us. Outside us we contemplate Him through His vestige, within us through His image and above us through the light which is sealed on our minds. This light is the light of the Eternal Truth since [as St. Augustine says] “our very mind is immediately formed by Truth itself.” Those who have been trained in the first mode of contemplation have already entered into the court before the Tabernacle; those who have been trained in the second have entered into the Holy Places; but those who have been trained in the third enter with the High Priest into the Holy of Holies, where above the ark are Cherubim of glory overshadowing the Propitiatory. By these Cherubim we understand the two modes or grades of contemplating the invisible and eternal things of God. One of them is turned to what belongs to the divine essence, while the other is turned to what is appropriated to the Divine Person. — from The Ascent of the Mind to God, Chapter V
St. Bonaventure (aka John of Fidanza) (1221–1274) was a Franciscan friar and Medieval theologian. More mystical in his approach to theology than his Dominican contemporary St. Thomas Aquinas, he nonetheless held many of the same views on doctrinal matters, making him with Aquinas the most important theologian of the Middle Ages. Relying heavily on the Platonic influences of St. Augustine in his work, St. Bonaventure is known for his subtlety of thought and for providing an alternative to the more strictly Aristotelian approach of Aquinas. He was declared a Doctor of the Church in 1588.