Justin Martyr: The Dialogue with Trypho - Chapter CV.—The Crucifixion and Last Prayers of Christ on Earth.
“And what follows of the Psalm,—‘But Thou, Lord, do not remove Thine assistance from me; give heed to help me. Deliver my soul from the sword, and my only-begotten from the hand of the dog; save me from the lion’s mouth, and my humility from the horns of the unicorns,’—was also information and prediction of the events which should befall Him. For I have already proved that He was the only-begotten of the Father of all things, being begotten in a peculiar manner Word and Power by Him, and having afterwards become man through the Virgin, as we have learned from the memoirs. Moreover, it is similarly foretold that He would die by crucifixion. For the passage, ‘Deliver my soul from the sword, and my only-begotten from the hand of the dog; save me from the lion’s mouth, and my humility from the horns of the unicorns,’ is indicative of the suffering by which He should die, i.e., by crucifixion. For the ‘horns of the unicorns,’ I have already explained to you, are the figure of the cross only. And the prayer that His soul should be saved from the sword, and lion’s mouth, and hand of the dog, was a prayer that no one should take possession of His soul: so that, when we arrive at the end of life, we may ask the same petition from God, who is able to turn away every shameless evil angel from taking our souls. And that the souls survive, I have shown [1 Sam. xxviii. 12, 13] to you from the fact that the soul of Samuel was called up by the witch, as Saul demanded. And it appears also, that all the souls of similar righteous men and prophets fell under the dominion of such powers, as is indeed to be inferred from the very facts in the case of that witch. Hence also God by His Son teaches us for whose sake these things seem to have been done, always to strive earnestly, and at death to pray that our souls may not fall into the hands of any such power. For when Christ was giving up His spirit on the cross, He said, ‘Father, into Thy hands I commend my spirit,’ [Luke xxiii. 46] as I have learned also from the memoirs. For He exhorted His disciples to surpass the pharisaic way of living, with the warning, that if they did not, they might be sure they could not be saved; and these words are recorded in the memoirs: ‘Unless your righteousness exceed that of the Scribes and Pharisees, ye shall not enter into the kingdom of heaven.' [Matt. v. 20]