This essay demonstrates that Athenagoras’ theology is primarily concerned, not with the creative activity of God, as L.W. Barnard has argued, but rather with the immateriality of the divine nature and the unity of the Father and the Son. It is this two-fold basis of distinction and unity that makes the apprehension of God possible only by mind and reason. Since the divine nature is heavenly and immaterial, such apprehension cannot occur in the physical realm as promoted in pagan worship, but must take place in the mind through the Son, who is the Logos or Mind, the Reason and Wisdom of the Father. Athenagoras’ assertion that the immaterial God can only be apprehended by reason emphasizes the distinction between God and matter, while the unity of the Father and Son in God’s acts and teachings highlights the role of reason in the soul’s apprehension of the divine. One must be conformed to the Son, who is the Reason of God, in order to apprehend God the Father, and Athenagoras evokes the ethical dimension of reason in the soul’s apprehension of the divine. As the soul follows the Son in obeying his teachings, it is conformed to the Son, thereby becoming rational and engaging in rational worship, focusing on the heavenly rather than the earthly. Thus it is in ethical conduct that Christians are essentially pure in spirit and rational in worship, as they are directed by the Son, who is unified with the Father, to apprehend the immaterial God.