“We believe, as is taught by the apostolical Church, in an only unbegotten Father, Who of His being hath no cause, immutable and invariable, and Who subsists always in one state of being, admitting neither of progression nor of diminution; Who gave the law, and the prophets, and the gospel; of patriarchs and apostles, and of all saints, Lord: and in one Lord Jesus Christ, the only-begotten Son of God, begotten not out of that which is not, but of the Father, Who is; yet not after the manner of material bodies, by severance or emanation, as Sabellius and Valentinus taught; but in an inexpressible and inexplicable manner, according to the saying which we quoted above, ‘Who shall declare His generation?’ since no mortal intellect can comprehend the nature of His Person, as the Father Himself cannot be comprehended, because the nature of reasonable beings is unable to grasp the manner in which He was begotten of the Father.