1.  Both men whose minds have been preoccupied by a heterodox creed and now wish to change over to the congregation of the orthodox, and also those who are now for the first time desirous of being instructed in the doctrine of truth, must be taught the creed drawn up by the blessed fathers in the Council which met at Nicæa.  The same training would also be exceedingly useful in the case of all who are under suspicion of being in a state of hostility to sound doctrine, and who by ingenious and plausible excuses keep the depravity of their sentiments out of view.  For these too this creed is all that is needed.  They will either get cured of their concealed unsoundness, or, by continuing to keep it concealed, will themselves bear the load of the sentence due to their dishonesty, and will provide us with an easy defence in the day of judgment, when the Lord will lift the cover from the hidden things of darkness, and “make manifest the counsels of the hearts.” 1 Cor. i. 5.  It is therefore desirable to receive them with the confession not only that they believe in the words put forth by our fathers at Nicæa, but also according to the sound meaning expressed by those words.  For there are men who even in this creed pervert the word of truth, and wrest the meaning of the words in it to suit their own notions.  So Marcellus, when expressing impious sentiments concerning the hypostasis of our Lord Jesus Christ, and describing Him as being Logos and nothing more, Marcellus of Ancyra (Angora) was represented to teach that the Son had no real personality, but was only the outward manifestation (Πορφορικὸς Λόγος) of the Father, but he could always defend himself on the ground that he was in communion with Julius and Athanasius, popes of Rome and Alexandria.  cf. Jer., De Vir. Ill. chap. lxxxvi. had the hardihood to profess to find a pretext for his principles in that creed by affixing an improper sense upon the Homoousion.  Some, moreover, of the impious following of the Libyan Sabellius, who understand hypostasis and substance to be identical, derive ground for the establishment of their blasphemy from the same source, because of its having been written in the creed “if any one says that the Son is of a different substance or hypostasis, the Catholic and Apostolic Church anathematizes him.”  But they did not there state hypostasis and substance to be identical.  Had the words expressed one and the same meaning, what need of both?  It is on the contrary clear that while by some it was denied that the Son was of the same substance with the Father, and some asserted that He was not of the substance and was of some other hypostasis, they thus condemned both opinions as outside that held by the Church.  When they set forth their own view, they declared the Son to be of the substance of the Father, but they did not add the words “of the hypostasis.”  The former clause stands for the condemnation of the faulty view; the latter plainly states the dogma of salvation.  We are therefore bound to confess the Son to be of one substance with the Father, as it is written; but the Father to exist in His own proper hypostasis, the Son in His, and the Holy Ghost in His, as they themselves have clearly delivered the doctrine.  They indeed clearly and satisfactorily declared in the words Light of Light, that the Light which begat and the Light which was begotten, are distinct, and yet Light and Light; so that the definition of the Substance is one and the same. cf. Letters xxxviii. and xcii.  Basil is anxious to show that his own view is identical with the Nicene, and does not admit a development and variation in the meaning of the word hypostasis; but on comparing such a passage as that in Athan. c. Afros, “hypostasis is substance, and means nothing else but very being” (ἡ δὲ ὑπόστασις οὐσία ἐστὶ καὶ οὐδὲν ἀλλὸ σημαινόμενον ἔχει ἢ αὐτὸ τὸ ὄν) with St. Basil’s words in the text it appears plain that hypostasis is not used throughout in the same sense.  An erroneous sense of “three hypostases” was understood to be condemned at Nicæa, though Athanasius, e.g. “In illud omnia,” etc., Schaff and Wace’s ed., p. 90, does himself use the phrase, writing probably about ten years after Nicæa; but he more commonly treats ουσία and ὑπόστασις as identical.  See specially the Tomus ad Antiochenos of a.d. 362 on the possible use of either “three hypostases” or “one hypostasis.”  cf. also n. on p. 179.  I will now subjoin the actual creed as it was drawn up at Nicæa. I give the creed in the original Greek.  The passages in brackets indicate the alterations of the Constantinopolitan revision according to the text of Chalcedon.