45 Luke, again, after mentioning how Pilate said, “I will therefore chastise him and let him go,” tells us that the whole multitude then cried out, “Away with this man, and release unto us Barabbas.” But perhaps they had not yet exclaimed, “Crucify him!” For Luke next proceeds thus: “Pilate therefore, willing to release Jesus, spoke again to them. But they cried, saying, Crucify him, crucify him!” This is understood to have been at the third hour. Luke then continues in these terms: “And he said unto them the third time, Why, what evil has he done?
I have found no cause of death in him: I will therefore chastise him and let him go. And they were instant with loud voices requiring that He might be crucified. And the voices of them prevailed.” Here, then, this evangelist also makes it quite evident that there was a great tumult. With sufficient accuracy for the purposes of my inquiry into the truth, we can further gather how long the interval was after which he spoke to them in these terms, “Why, what evil has he done?” And when he adds thereafter, “They were instant with loud voices, requiring that He might be crucified, and the voices of them prevailed,” who can fail to perceive that this clamour was made just because they saw that Pilate was unwilling to deliver the Lord up to them?
And, inasmuch as he was exceedingly reluctant to give Him up, he did not certainly yield at present in a moment, but in reality two hours and something more were passed by him in that state of hesitancy.
Source: The Harmony of the Gospels (New Advent)