I have devised a test to quickly determine whether someone holds to a Nestorian Christology.  Ask, “What would have happened to Jesus’ body if the Spirit would have departed from it prior to Jesus’ death on the cross?”  If they answer that Jesus would have continued to live and function, they hold to a Nestorian Christology.  Here’s why:

The presence of a person is required for a human body to live and function.  If the divine person has departed, necessarily there must be a second person who co-existed alongside the divine person that remains, and continues to be the source of life and function.  Who would that second person be?  Presumably the human person of Jesus.  But if there was a human person co-existing alongside the divine person in Jesus, then Jesus is not a single person, but two persons = Nestorianism.

If Jesus is a single person—the person of God incarnate—then Jesus could not have continued to live if the Spirit of God departed from His body, in the same way that you and I could not go on living if our spirits departed from our bodies.  If the Spirit of God had ever departed from Jesus’ body prior to His death on the cross, Jesus would have never even made it to the cross!  That’s why we can be confident that when Jesus says, “My God, my God, why have you forsaken me?”, Jesus did not mean God had literally and physically forsaken Him.  If He had physically forsaken Jesus, Jesus could not have even asked the question because Jesus would no longer be alive.