12 But perchance with the fearfulness of human ignorance, He feared the very power of death, which He possessed; so, though He died of His own accord, He feared because He was to die. If any think so, let them ask “To which was death terrible, to His Spirit or to His body?” If to His body, are they ignorant that the Holy One should not see corruption, that within three days He was to revive the temple of His body? But if death was terrible to His Spirit, should Christ fear the abyss of hell, while Lazarus was rejoicing in Abraham's bosom? It is foolish and absurd, that He should fear death, Who could lay down His soul, and take it up again, Who, to fulfil the mystery of human life, was about to die of His own free will. He cannot fear death Whose power and purpose in dying is to die but for a moment: fear is incompatible with willingness to die, and the power to live again, for both of these rob death of his terrors.
Source: On the Trinity (New Advent)