Passion of God and Christ

Θεοῦ πάθος οὐ λέγεται· Χριστοῦ γὰρ τὸ πάθος γέγονε· σαρκωθέντος δηλονότι Θεοῦ, καὶ τῇ προσλήψει τῆς σαρκὸς τὸ πάθος ὑπομείναντος. Θεότης γὰρ γυμνὴ οὐ μόνον πάσχειν οὐ δύναται, ἀλλ' οὕτε κρατεῖσθαι, οὐδὲ ὁρᾶσθαι, εἰ μὴ τῇ φύσει τῶν ἀνθρώπων ἠνώθη φιλανθρώπως. Ἅγιος Ἰσίδωρος Του Πηλουσιώτου, Βιβλιον Πρῶτον, Ἐπιστολὴ ΡΚΔ' Δωροθεω Κομητι

It is not said' the passion of God', for it was the passion of Christ; manifest it is that with the incarnation of God was the taking on of flesh liable to suffering. For not only is the Divinity unable to suffer, but it cannot be  grasped or envisioned unless it had been bound to human nature out of kindness and mercy. Saint Isidore of Pelusium, Book 1, Letter 124, To Count Dorotheus