“But do not think I will accuse you before the Father. Your accuser is Moses, on whom your hopes are set. If you believed Moses, you would believe me, for he wrote about me. But since you do not believe what he wrote, how are you going to believe what I say?”
Here we come to the nub of the Jews' unbelief. It was how they read the books of Moses. Instead of seeing them as pointing forwards to the Messiah, they read them as if they were sufficient unto themselves. The point is not that keeping the Law is sufficient to please God, because nobody can and the temporary plug in the gap, namely the sacrifice of animals can never assuage the anger of God. It takes God himself in the person of Jesus to atone for the sins of the world.
At the last Assize it will not be Jesus who accuses but Moses himself, because as plain as he could be he was still distorted. He pointed forwards to Jesus but the Jews effectively turned him into a demi-god and worshiped the product rather than the Creator; the creation rather than the Redeemer.