For if our Lord, when enjoining the baptism of salvation, charged His disciples to baptize all nations in the name “of the Father and of the Son and of the Holy Ghost,” Matt. xxviii. 19. not disdaining fellowship with Him, and these men allege that we must not rank Him with the Father and the Son, is it not clear that they openly withstand the commandment of God?  If they deny that coordination of this kind is declaratory of any fellowship and conjunction, let them tell us why it behoves us to hold this opinion, and what more intimate mode of conjunction The word used is συνάφεια, a crucial word in the controversy concerning the union of the divine and human natures in our Lord, cf. the third Anathema of Cyril against Nestorius and the use of this word, and Theodoret’s counter statement (Theod. pp. 25, 27).  Theodore of Mopsuestia had preferred συνάφεια to ἕνωσις; Andrew of Samosata saw no difference between them.  Athanasius (de Sent. Dionys. § 17) employs it for the mutual relationship of the Persons in the Holy Trinity:  “προκαταρκτικὸν γάρ ἐστι τῆς συναφείας τὸ ὄνομα.” they have.