If you decide to take ALL of Jesus’ words as being of equal importance then you have to at least acknowledge that Jesus claimed to be God. And when you do that, then everything God says in the Old Testament then also becomes things that Jesus said. If this logic is correct then shouldn't the Old Testament be of equal importance to the New Testament?
Now, I agree that if we are to take Jesus' words as true, then we must acknowledge that He claims to be divine. The problem with the argument above comes at the leap from this acknowledgement to the assumption we must then deem everything in the Old Testament as the coming from Jesus. This is false and a misunderstanding of how the Bible was written and inspired by God.
The Bible has both true human authors and a true divine author (the Holy Spirit). The Holy Spirit does not take away any of the human authors' free will in inspiring them to write Sacred Scripture. Rather, the Holy Spirit works through the human writers of Scripture, using their limited intellect and understanding of the world, to write the truth about God's plan. The Catechism says:
God inspired the human authors of the sacred books. "To compose the sacred books, God chose certain men who, all the while he employed them in this task, made full use of their own faculties and powers so that, though he acted in them and by them, it was as true authors that they consigned to writing whatever he wanted written, and no more." - CCC, 106The Holy Spirit did not force the human authors of Scripture to write down whatever he told them - a common image portraying this wrong thinking is a dove speaking into the ear of a one of the Gospel writers. Rather, God worked with and through the human authors to write truth.
Also, the revelation of God through Sacred Scripture is progressive. So, the Old Testament is incomplete and does not contain the full revelation of God. Is it true? Yes. But, you have to read it in light of the fullness of revelation offered through Christ. The Catechism says this about the Old Testament:
Indeed, "the economy of the Old Testament was deliberately so oriented that it should prepare for and declare in prophecy the coming of Christ, redeemer of all men." "Even though they contain matters imperfect and provisional,"94 the books of the Old Testament bear witness to the whole divine pedagogy of God's saving love: these writings "are a storehouse of sublime teaching on God and of sound wisdom on human life, as well as a wonderful treasury of prayers; in them, too, the mystery of our salvation is present in a hidden way." - CCC, 122When we read the Old Testament, we ought to always understand that the authors of those books had limited understanding of the nature of God, God's plan for creation, man's dignity in Christ, etc. Thus, the Old Testament cannot be said to be equal to the New Testament, because of the limitations I have described.
So, to say that the words of Christ = the books of the Old Testament is an inaccurate and incomplete statement based on a faulty understanding of Sacred Scripture and how God reveals Himself and His plan to His people.
I hope this helps.