[Jesus said,] No one takes [my life] from me, but I lay it down of my own accord. I have authority to lay it down and authority to take it up again. This command I received from my Father. (John 10:18)
In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things came into being through him, and without him not one thing came into being. (John 1:1-3)
Because Jesus is the Word, and all things came into being through him, it is not surprising that his going out of being was under his control as well. In him is Life; in him, also, is Death.
We believe that Jesus’s death, and his resurrection, his re-life, are the central points of human, and even cosmic, history. It was God’s plan from ‘before’ the beginning of time that Jesus would come into human being, and then die, and then live again. Again, it is not surprising that Jesus chose the moment and place of his own death.
And what a hard and horrible choice he made: to die after torture and shame, to die via torture and shame. No wonder Julian desired to suffer as Jesus did; she was trying to understand such a great love as this.
Then came suddenly to my mind that I should desire … that my body might be fulfilled with mind and feeling of His blessed Passion. For I would that His pains were my pains, with compassion and afterward longing to God. But in this I desired never bodily sight nor shewing of God, but compassion such as a kindred soul might have with our Lord Jesus, that for love would be a mortal man: and therefore I desired to suffer with Him.