For when God said: “Let there be light,” rational light arose, that is, the angels, those who remained true to him as well as those who fell into outer darkness where there was no light, because they denied that God was the true light shining before eternity and without beginning, and because they wanted to make someone like him which was impossible. Then God called another life into existence which he clothed with a body, humanity, to whom he gave both the place and the glory of the lost angel, to achieve in praise of God what the other had refused to do. So angels are shown with a human form because they are devoted to the world in body, yet serve God continually in the spirit, nor, just because they are detained physically in the physical world, do they forget that they are spirits in the service of God. And their faces are turned to the east because being both spiritual and worldly, and as servants of God desiring to preserve their souls in life, they must turn toward the source of holy living and happiness.

– Saint Hildegard of Bingen (+1179)