This passage comes after a description of the noetic pursuit of transcendent truth by all of the Greek philosophers, upward and away from the earth. This central theme of noetic ascent is summarized (with appreciation) from the Presocratics through Aristotle, before Foltz turns to incarnation:
Into this trajectory of restless, almost obsessive, transcendence comes the peaceful image (eikon) of the Nativity, a different face of being. That God has really entered into creation—not appeared by proxy like some ephemeral projection, but come into being within the earthly—is visually rendered in the iconographic tradition of the Christian East through subterranean imagery. The Eternal Logos enters substantially into creation kenotically, innocently, as a little child, represented by Mary tending to her child while inscribed deep within the Earth, in a cave, a birthplace written into the essential materiality of the Earth: Incarnation or embodiment itself is taking place within the earth, the principle of all embodiment. Home and inhabitation and immanence on the one hand, and divinity and transcendence and longing on the other, are no longer in incommensurable ends of meaning, metaphysical oil and water, but are held in a serene balance.The Noetics of Nature: Environmental Philosophy and the Holy Beauty of the Visible by Bruce Foltz.