Text edited by Rev. Alexander Roberts and James Donaldson and first published by T&T Clark in Edinburgh in 1867. Additional introductionary material and notes provided for the American edition by A. Cleveland Coxe, 1886.
Translator's Biographical Notice[a.d. 260. I can add nothing but conjectures to the following: ] Of this Theognostus we have no account by either Eusebius or Jerome. Athanasius, however, mentions him more than once with honour. Thus he speaks of him as ane` r lo'gios, an eloquent or learned man.  And again as Theo'gnostos ho thauma'sios kai` spoudaios, the admirable and zealous Theognostus.  He seems to have belonged to the Catechetical school of Alexandria, and to have flourished there in the latter half of the third century, probably about a.d. 260. That he was a disciple of Origen, or at least a devoted student of his works, is clear from Photius.  He wrote a work in seven books, the title of which is thus given by Photius:  The Outlines of the blessed Theognostus, the exegete of Alexandria. Dodwell and others are of opinion that by this term exegete,  is meant the presidency of the Catechetical school and the privilege of public teaching; and that the title, Outlines, was taken from Clement, his predecessor in office. According to Photius, the work was on this plan. The first book treated of God the Father, as the maker of the universe; the second, of the necessary existence of the Son; the third, of the Holy Spirit; the fourth, of angels and demons; the fifth and sixth, of the incarnation of God; while the seventh bore the title, On God's Creation. Photius has much to say in condemnation of Thegnostus, who, however, has been vindicated by Bull and Prudentius Maranus. Gregory of Nyssa has also charged him with holding the same error as Eunomius on the subject of the Son's relation to the work of creation. He is adduced, however, by Athanasius as a defender of the Homousian doctrine.
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The substance  of the Son is not a substance devised extraneously,  nor is it one introduced out of nothing;  but it was born of the substance of the Father, as the reflection of light or as the steam of water. For the reflection is not the sun itself, and the steam is not the water itself, nor yet again is it anything alien; neither is He Himself the Father, nor is He alien, but He is  an emanation  from the substance of the Father, this substance of the Father suffering the while no partition. For as the sun remains the same and suffers no diminution from the rays that are poured out by it, so neither did the substance of the Father undergo any change in having the Son as an image of itself.
Theognostus, moreover, himself adds words to this effect: He who has offended against the first term  and the second, may be judged to deserve smaller punishment; but he who has also despised the third, can no longer find pardon. For by the first term and the second, he says, is meant the teaching concerning the Father and the Son; but by the third is meant the doctrine committed to us with respect to the perfection  and the partaking of the Spirit. And with the view of confirming this, he adduces the word spoken by the Saviour to the disciples: "I have yet many things to say unto you, but ye cannot bear them now. But when the Holy Spirit is come, He will teach you." 
Then he says again: As the Saviour converses with those not yet able to receive what is perfect,  condescending to their littleness, while the Holy Spirit communes with the perfected, and yet we could never say on that account that the teaching of the Spirit is superior to the teaching of the Son, but only that the Son condescends to the imperfect, while the Spirit is the seal of the perfected; even so it is not on account of the superiority of the Spirit over the Son that the blasphemy against the Spirit is a sin excluding impunity and pardon, but because for the imperfect there is pardon, while for those who have tasted the heavenly gift,  and been made perfect, there remains no plea or prayer for pardon.
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