As I have shared with you, it is our belief that it was through a Hypostatic Union that God, in the Person of Jesus Christ, is both God and Man. The hypostatic union implies that the Logos made humanity His own in its totality; thus the Second  Person of the Trinity was indeed the subject, or agent, of the   human experiences, or acts, of Jesus. The controversy between Cyril of Alexandria and Nestorius concerning the term Theotokos, applied to the Virgin Mary, concerned essentially this very problem. Was there, in Jesus, a human person whose mother could have been Mary? Cyril’s answer –   emphatically negative – was, in fact, a Christological option of great importance. In Christ, there was only one Son, the Son of God, and Mary could not have been the Mother of anyone else. She was, therefore, indeed the “Mother of God.” Exactly the same problem arose in connection with the death of Christ. Impassibility and immortality were indeed characteristics of the divine nature. How, then, asked the theologians of Antioch, could the Son of God die? Obviously, the “subject” of Christ’s death was only His humanity. Against this point of view, and following Cyril, the fifth Council (553) affirms: “If anyone does not confess that our Lord Jesus Christ who was crucified in the flesh is true God and the Lord of Glory and one of the Holy Trinity, let him be anathema.” This conciliar text, which paraphrases 1 Corinthians 2:8 (If they had understood, they would never have crucified the Lord of glory), inspired the hymn “The Only-Begotten Son,” attributed to Emperor Justinian and sung at every Byzantine Eucharistic Liturgy: “One of the Holy Trinity, You were crucified for us.”

Theopaschism – the acceptance of formulae which affirm that the “Son of God died in the flesh” – illustrates how distinct the concepts of hypostasis and nature or essence really are. The distinction is stressed by one of the main Chalcedonian theologians, Leontius of Jerusalem: The Logos is said to have suffered according to the hypostasis, for within His hypostasis He assumed a passible human essence besides His own impassible essence, and what can be asserted of the human essence can be asserted of the hypostasis. What this implies is that the characteristics of the divine essence – impassibility, immutability, etc – are not absolutely binding upon the personal, or hypostatic, existence of God. The affirmation that the Son of God indeed “died in the flesh” reflects, better than any other Christological formula, the boundlessness of God’s love for man, the reality of the “appropriation” by the Logos of fallen and mortal humanity – i.e., the very mystery of salvation.

While this may be difficult to understand, I would encourage you to not give up and wrestle with it.