When, to his enumeration of those to whom he would send us, he adds, “What saying equal to these did your god utter under sufferings?” we would reply, that the silence of Jesus under scourgings, and amidst all His sufferings, spoke more for His firmness and submission than all that was said by the Greeks when beset by calamity. Perhaps Celsus may believe what was recorded with all sincerity by trustworthy men, who, while giving a truthful account of all the wonders performed by Jesus, specify among these the silence which He preserved when subjected to scourgings; showing the same singular meekness under the insults which were heaped upon Him, when they put upon Him the purple robe, and set the crown of thorns upon His head, and when they put in His hand a reed in place of a sceptre: no unworthy or angry word escaped Him against those who subjected Him to such outrages.
Since, then, He received the scourgings with silent firmness, and bore with meekness all the insults of those who outraged Him, it cannot be said, as is said by some, that it was in cowardly weakness that He uttered the words: “Father, if it be possible, let this cup pass from Me: nevertheless, not as I will, but as You will.” The prayer which seems to be contained in these words for the removal of what He calls “the cup” bears a sense which we have elsewhere examined and set forth at large.
But taking it in its more obvious sense, consider if it be not a prayer offered to God with all piety. For no man naturally regards anything which may befall him as necessary and inevitable; though he may submit to what is not inevitable, if occasion requires. Besides, these words, “nevertheless, not as I will, but as You will,” are not the language of one who yielded to necessity, but of one who was contented with what was befalling Him, and who submitted with reverence to the arrangements of Providence.
Source: Against Celsus (New Advent)