Understand. Jesus says that The Scriptures or the Old Testament is about Him and He says in John 3:16 that He is the One to believe to be saved. Jesus spoke. What does Jesus say? A lot! Yet, in parables!
THE SCRIPTURES aka THE OLD TESTAMENT IS NOT AN OBSOLETE
The Scriptures of the Jews, as Jesus refers to them, are the compilation of the writings of Moses and of the Prophets, and the Psalms, and other historical books. The Immutable Holy Scriptures Textbook is about the immutable strategy for the salvation of Jesus, according to His declarations in John 5:39, not the salvation of anyone else. It is about how God the Father offered Him (1 Corinthians 5:17) as the sacrificial ransom to rescue any willing man who chooses to believe in Him (John 3:16) from eternal destruction to eternal life and about what Jesus teaches us to follow and do so that He can rescue us if we overcome the odds (John 14:6, Revelation 3:21).
THE NEW TESTAMENT DOES NOT, CANNOT REPLACE THE OLD TESTAMENT OR THE SCRIPTURES. Matthew 5:17-18
THE NEW TESTAMENT WRITES ABOUT THE FULFILLMENT OF THE SCRIPTURES AND IS ABOUT THE NEW COMMANDMENT THAT JESUS GAVE US, WHICH IS, 'LOVE ONE ANOTHER'.
NO DISCIPLE, NO APOSTLE, NO WRITER IN THE NEW TESTAMNET HAS THE AUTHORITY TO CHANGE ANY IOTA IN THE PLAN OF SALVATION WHICH IS COMMUNICATED THROUGH MOSES AND THE PROPHETS AND PROCLAIMED TO THE WORLD BY THE APOSTLES. NOT EVEN JESUS COULD HAVE CHANGED ANY IOTA IN THE HOLY SCRIPTURES. YES! EVEN JESUS! WHY? Deuteronomy 4:2, 5:32, 12:32, Matthew 5:17-18, et cetera.
YHWH (Jesus) upheld Moses and the Prophets in the parable of Lazarus and the rich man in Luke 16:29-31 and in Matthew 5:17-18, et cetera. Therefore, we can never read that any Apostle or any writer has written anything contrary to what is written in Moses and the Prophets.
The New Testament records the teachings of Jesus from God the Father for our salvation and the records of the communication of the same teachings by His Apostles to the world. Any theological biblical point made in the New Testament by the Apostles is supported by quotes from the Holy Scriptures.
The goal of the THST is to keep us in the path of Salvation of Jesus (YHWH) to overcome every single iota of evil or misinformation to qualify for His grace because He says that the ones who will be saved are the ones who do ONLY the will of God the Father (Matthew 7:21).
CONCLUSION
THST (The Holy Scriptures Textbook) is a Textbook that YHWH as God and in flesh, the Prophets, and the Disciples write to elucidate what it takes to be saved by MESSIAH YHWH Jesus (Luke 2:11, John 3:16, Romans 10:9-11, Philippians 2:11, Matthew 7:21).
Many in the belief or faith of Jesus, whenever they choose to disobey a commandment of the Scriptures (aka Old Testament), are quick to point out that such commandment is in the Old Testament not in the New Testament of their Savior Jesus. To be plainly honest, those who reject any iota of the THST are blinded and misguided by Satan with false reasoning, as he did to Adam and Eve. Any hint that the Apostles suggest any adjustment to Moses must come from a misguided disguised messenger of light, based on the declarations in Matthew 5:17-18, Luke 16:29-31, Deuteronomy 4:2, 5:32, 12:32, et cetera, when we know that it is clear that not even Jesus may make a change to the plan of salvation (Matthew 5:17-18, John 12:50).
We must understand that when we read that Jesus came to fulfill, it does not mean that He came to loosen or make Moses easier in any way by lifting forbiddance and abolishing other requirements. In other words, if we were to rewind time to follow the symbolism of the plan of salvation in Moses, everything in the rituals would have remained the same.
THE UNCHANGEAGLE, ETERNAL, IMMUTABLE WORD OF GOD IN MOSES WHICH IS MORE SOLID THAN THE UNIVERSE.
Deuteronomy 4:1-2 ASV
(1) And now, O Israel, hearken unto the statutes and unto the ordinances, which I teach you, to do them; that ye may live, and go in and possess the land which Jehovah, the God of your fathers, giveth you.
(2) Ye shall not add unto the word which I command you, neither shall ye diminish from it, that ye may keep the commandments of Jehovah your God which I command you.
Deuteronomy 5:31-33 ASV
(31) But as for thee, stand thou here by me, and I will speak unto thee all the commandment, and the statutes, and the ordinances, which thou shalt teach them, that they may do them in the land which I give them to possess it.
(32) Ye shall observe to do therefore as Jehovah your God hath commanded you: ye shall not turn aside to the right hand or to the left.
(33) Ye shall walk in all the way which Jehovah your God hath commanded you, that ye may live, and that it may be well with you, and that ye may prolong your days in the land which ye shall possess.
Deuteronomy 12:32 ASV
(32) What thing soever I command you, that shall ye observe to do: thou shalt not add thereto, nor diminish from it.
Matthew 5:17-18 ASV
(17) Think not that I came to destroy the law or the prophets: I came not to destroy, but to fulfil.
(18) For verily I say unto you, Till heaven and earth pass away, one jot or one tittle shall in no wise pass away from the law, till all things be accomplished.
Matthew 28:19-20 ASV
(19) Go ye therefore, and make disciples of all the nations, baptizing them into the name of the Father and of the Son and of the Holy Spirit:
(20) teaching them to observe all things whatsoever I commanded you: and lo, I am with you always, even unto the end of the world.