Whether Christ was slain by another or by Himself?

Objections

Objection 1 : It would seem that Christ was not slain by another, but by Himself. For He says Himself (Jn. 10:18): "No men taketh My life from Me, but I lay it down of Myself." But he is said to kill another who takes away his life. Consequently, Christ was not slain by others, but by Himself.
Objection 2 : Further, those slain by others sink gradually from exhausted nature, and this is strikingly apparent in the crucified: for, as Augustine says (De Trin. iv): "Those who were crucified were tormented with a lingering death." But this did not happen in Christ's case, since "crying out, with a loud voice, He yielded up the ghost" (Mt. 27:50). Therefore Christ was not slain by others, but by Himself.
Objection 3 : Further, those slain by others suffer a violent death, and hence die unwillingly, because violent is opposed to voluntary. But Augustine says (De Trin. iv): "Christ's spirit did not quit the flesh unwillingly, but because He willed it, when He willed it, and as He willed it." Consequently Christ was not slain by others, but by Himself.