Saint Peter Chrysologus (around 406-450), Bishop of Ravenna, Doctor of the Church Sermon 3
“You have a greater than Jonah here.” It was Jonah himself who decided to be thrown out of the boat: “Pick me up and throw me into the sea,” he said (Jon 1:12), which points to the passion of the Lord Jesus, which he freely took upon himself. For why did the sailors wait to be given the order…? It is because, when the salvation of all requires the death of one single person, that death depends on the free decision of the person concerned… Thus, in this story, which completely prefigures the Lord’s story, they await the decision of the person who must die, so that his death might not be a necessity to which he submits, but a free act: “I have power to lay down my life, and I have power to take it up again. No one takes it from me,” (Jn 10:18) says the Lord. For when Christ delivered over his spirit (Jn 19:30), it was not because his life was slipping away from him. He who holds in his hands the soul of every person could not lose his own. The prophet said: “I constantly hold my life in your hands.” (Ps 119:109) And in another place: “Into your hands I commend my spirit.” (Ps 31:6; Lk 23:46)
This excerpt that came with today's USCCB daily gospel email, touches on the massive (and so easily overlooked distinction) between Christ's death and anyone else's. He alone had the power to lay down his life. This may be semi-heretical, but it seems that Jesus makes it clear no one could kill him. Judas didn't kill him. The Jews didn't kill him. Rome didn't kill him.
But, even more radical, Jesus didn't kill himself. He alone of all human beings had the claim to own his own life, and with that claim the ability and right to surrender it. Suicide is sinful specifically because we do not own ourselves. Our whole person (body and spirit) belongs to God. Since Jesus is one with the Father, his life was his own and he could do with it as he saw fit. What he saw fit to do was the will of the Father - and the will of the Father had been prefigured by the cries from the sea that Jonah be thrown into it. Jonah surrendered himself to this fate, but did not seek to kill himself. Christ surrendered his spirit on the cross to the the will of the Father, in the final holocaust of Mercy. He laid down what belonged to the life of the Trinity, and what it would have been objectively impossible for any human being to take from him.