No kidding! Jesus told the Jews that Moses allowed certain things due to the hardness of their hearts; Jesus said you have heard that it was written, and followed up by saying unto them something different than what was written. So Soyeong is a false teacher, who even says the 613 mitzvot are written on our hearts, which is one of the most ridiculous things I have heard.
In Matthew 4, Jesus consistently proceeded a quote from what was written by saying "it is written...", but it Matthew 5, he consistently proceeded a quote from what they people had heard being said by saying "you have heard that it was said...", so his emphasis on the different form of communication is important. Jesus was not sinning in violation of Deuteronomy 4:2 by making changes to what was written, but rather he was fulfilling the law by correcting what the people had heard being said and by teaching how to correctly obey what was written as it was originally intended. For example:
Matthew 5:43 “You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’
While what was written does instruct us to love our neighbor (Leviticus 19:18), it does not instruct us to hate our enemy, so that is what Jesus was correcting. Rather, loving our enemy is in accordance with verses like Exodus 23:4-5, Deuteronomy 23:7, Proverbs 24:17-18, and Proverbs 25:21-22.
In Deuteronomy 13:1-5, the way that God instructed His people to determine that someone is a false prophet who is not speaking for him was if they taught against obeying the Mosaic Law, so I am not the one who is a false teacher. In Jeremiah 31:33, it directly states that God will put the Mosaic Law in our minds and write it on our hearts, so I don't see how you can say that that is one of the most ridiculous things that you have ever heard. Those who want nothing to do with obeying the Mosaic Law want nothing to do with the New Covenant.
There is a great deal of blindness involved, to be sure, since they have put themselves under the law and fallen from grace/been severed from Christ. Jesus brought the temple system and the relevance of Judaism to an end, but some such as S think that we should practice a dead thing, and that we should walk as Jesus did, as if they can and do, showing us how delusional they really are, since I doubt very much that they calm violent storms, heal leapers, give sight to the blind, restore hearing and speech to the deaf and mute, turn water to wine, raise the dead, etc, etc. They pretend to follow Jesus while ignoring His teaching about putting new wine into an old wine skin. They ignore that Jesus said not to sew a new patch onto old cloth. They lack understanding and teach their falseness instead of Truth.
You want do call me blind, but I'm not the one who is interpreting God's word as speaking against obeying God and the blind never connects obedience to God with blindness, but just the opposite. God is sovereign, so we are all under His law and are obligated to refrain from doing what God has revealed to be sin regardless of whether or not we consider ourselves to be under it. In Psalms 119:29, he wanted God to be gracious to him by teaching him to obey the Mosaic Law, so that is the way to be under grace, not the way to fall from it. Christ set a sinless example for how to follow of how to walk in obedience to the Mosaic Law, so it is absurd to think that the way to be severed from Christ is by following him. Judaism is the religion based on following God's word and Jesus did not put God's word to an end, but rather he is God's word made flesh. In 1 Peter 2:21-22, we are told to follow Christ's example, in 1 John 2:6, those who are in Christ are obligated to walk in the same way he walked, and in 1 Corinthians 11:1, we are instructed to be imitators of Paul as he is of Christ, which is not about performing miracles, but about walking in obedience to the Mosaic Law. Jesus gave the parable about the wineskins to answer the question of why his disciples were not fasting, which has nothing to do with the point that you are trying to use his parable to make, so you are the one who is ignoring his teachings. In Palms 119:142, the Mosaic Law is truth, but you are opposed to truth.