13.  Be not ashamed to confess thine ignorance, since thou sharest ignorance with Angels.  Only He who begat knoweth Him who was begotten, and He who is begotten of Him knoweth Him who begat.  He who begat knoweth what He begat:  and the Scriptures also testify that He who was begotten is God I have followed the reading of Codd. Coisl. Roe, Casaub. Mon. A., which is approved though not adopted by the Benedictine Editor.  The common text is manifestly interpolated:  “And the Holy Spirit of God testifies in the Scriptures, that He who was begotten without beginning is God.  For what man knoweth, &c.”  This insertion of 1 Cor. ii. 11 interrupts the argument, and is a useless repetition of the allusion to the same passage in § 12..  For as the Father hath life in Himself, so also hath He given to the Son to have life in Himself John v. 26.; and, that all men should honour the Son, even as they honour the Father Ib. v. 23.; and, as the Father quickeneth whom He will, even so the Son quickeneth whom He will Ib. v. 21..  Neither He who begat suffered any loss, nor is anything lacking to Him who was begotten (I know that I have said these things many times, but it is for your safety that they are said so often):  neither has He who begat, a Father, nor He who was begotten, a brother.  Neither was He who begat changed into the Son See iv. 8, note 8, on the Sabellian doctrine, and Athanas. (de Synodis, § 16, note 10 in this series)., nor did He who was begotten become the Father The doctrine of Sabellius might be expressed in two forms, either the Father became the Son, or the Son became the Father.  Both forms are here denied.  The Jerusalem Editor thinks there is an allusion to the Arian argument mentioned by Athanasius (c. Arian. Or. I. cap. vi. 22):  “If the Son is the Father’s offspring and Image, and is like in all things to the Father, then it necessarily holds that as He is begotten so He begets, and He too becomes father of a son.”  But the close connexion of the two clauses is in favour of the reference to the Sabellian υἱοπατορία..  Of One Only Father there is One Only-begotten Son:  neither two Unbegotten ἀγέννητοι.  The context shews that this, not ἀγένητοι, is here the right form.  Athanasius seems to have used ἀγέννητος in both senses “Un-begotten,” as here, and “unoriginate.”  Thus (c. Arian. Or. i. cap. ix. § 30) he says of the Arians:  “Their further question ‘whether the Unoriginate be one or two,’ shews how false are their views.”  Compare Bp. Lightfoot’s Excursus on Ignatius, Ephes. § 7, and Mr. Robertson’s notes on Athanasius in this Series., nor two Only-begotten; but One Father, Unbegotten (for He is Unbegotten who hath no father); and One Son, eternally begotten of the Father; begotten not in time, but before all ages; not increased by advancement, but begotten that which He now is.