It is written in the prophets (Isa 54:13). This is not a direct quote from any of the prophets. Jesus certainly knew the exact wording as did the Jews He is addressing (who did not rebuke Him for His incorrect quote). How can Jesus legitimately say that the following is written in the prophets when it isn’t? Does this give you any insight into how you should study God’s word?

Isa 54:13  All your sons will be taught by the LORD, and great will be your children’s peace.

This passage Jesus loosely quoted was understood to apply to the times of the Messiah and is indeed an aspect of the New Covenant the Messiah cut for us (Jer 31:33,34), but it also applied to any of His hearers that would follow Him. The Isaiah passage is addressed to the city of God and its inhabitants, but prophetically to the church. God had given the law as a tutor to lead the people to Christ as He had sent the prophets before them for the same purpose. Gal 3:24 Those who listened to what the Father had said and learned from it, would come to Jesus. Note the word “and”. It is possible to listen to what God says and not learn from it. Only those who are truly taught of God will come to Jesus. If these were not coming to Him, it was their own fault for not learning from what God had told them through the law, the prophets, the signs Jesus gave, and the words of God which Jesus had spoken.

Jer 31:33-34  “This is the covenant that I will make with the house of Israel after that time,” declares the LORD. “I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people. No longer will a man teach his neighbour, or a man his brother, saying, ‘Know the LORD,’ because they will all know me, from the least of them to the greatest,” declares the LORD. “For I will forgive their wickedness and will remember their sins no more.”

Ga 3:24  So the law was put in charge to lead us to Christ that we might be justified by faith.