13 Let then our Head say, “False witnesses did rise up, they laid to My charge things that I knew not”. But let us say to our Head, Lord, what knew Thou not? Did Thou indeed know not anything? Did You not know the hearts of them that charged You? Did You not foresee their deceits? Did You not give Yourself into their hands knowingly? Had You not come that You might suffer by them? What then knew Thou not? He knew not sin, and thereby He knew not sin, not by not judging, but by not committing.
There are phrases of this kind also in daily use, as when you say of any one, He knows not to stand, that is, he does not stand; and, He knows not to do good, because he does not good; and, He knows not to do ill, because he does not ill....What knew not Christ so much, as to blaspheme? Thereof was He called in question by His persecutors, and because He spoke truth, He was judged to have spoken blasphemy. But by whom? By them of whom it follows, “They rewarded Me evil for good, and barrenness to My Soul”.
I gave unto them fruitfulness, they rewarded Me barrenness; I gave life, they death; I honour, they dishonour; I medicine, they wounds; and in all these which they rewarded Me, was truly barrenness. This barrenness in the tree He cursed, when seeking fruit He found none. Leaves there were, and fruit there was not: words there were, and deeds there were not. See of words abundance, and of deeds barrenness. “Thou that preachest a man should not steal, stealest: thou that sayest a man should not commit adultery, committest adultery.” Such were they who charged Christ with things that He knew not.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)