Isaiah And The Incarnation

Τῇ λαβίδι ἔλαβεν ὁ διορατικώτατος Ἡσαῖας τὸν ἐκ τοῦ θυσιαστηρίου ἄνθρακα, τὴν τοῦ Κυρίου ἡμῶν ἐνανθρώπησιν θεωρῶν τηλαυγέστατα. Ἄνθραξ ἠ θεία ἐωρὰτο οὐσία· λαβὶς δὲ ἡ ἐξ ἡμῶν αὐτῇ ἐνωθεῖσα ἀναμάρτητος σάρξ. Ἥψατο δὲ τῶν χειλέων Ἥσαῖου, καὶ τὰς αὐτοῦ ἐκάθηρεν ἁμαρτίας, τὰς πάσης τῆς ἀνθρωπείας φύσεως δηλονότι. Ἡ γὰρ ἄῥῥητος τοῦ λόγου πρὸς τὸ ἀνθρώπινον ἔνωσις ἦρε θεοπρεπῶς τὰς τοῦ κόσμου παντὸς ἁμαρτίας. Ἅγιος Ἰσίδωρος Του Πηλουσιώτου, Βιβλιον Πρῶτον, Ἐπιστολή ΜΒ' , Ἀρχοντιῳ Μονακῳ Source: Migne PG 78.208d-209a

In the bringing of the coal in the forceps from the altar to Isaiah 1 the most perceptive may most clearly see the incarnation of the Lord. By the coal is indicated the Divine essence, and by the forceps the flesh without taint of sin, to which, taking it from us, He was joined. And it touches the lips of Isaiah it purges his sin, that is, clearly all human nature, for the conjunction of human nature with the Word, which no words are able to explain, is the consent of the the Divine to take up the sins of the whole world. Saint Isidore of Pelusium, Book 1, Letter 42, To Archontius the Monk 1 Isaiah 6.6