Haven’t we learned anything from the OT and just how right and just how wrong a “magisterium”/tradition, God’s annointed carriers of promise and truth, can be ?
We have learned a lot. In the NT, Jesus Christ changes everything, protecting his Church from all error. This includes the Father giving the Son all authority and the Son giving authority to his Church.
16 Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed them. 17 And when they saw him they worshiped him; but some doubted. 18 And Jesus came and said to them, “All authority in heaven and on earth has been given to me."
And Jesus gives this authority to the apostles, to forgive sins
21 Jesus said to them again, “Peace be with you. As the Father has sent me, even so I send you.” 22 And when he had said this, he breathed on them, and said to them, “Receive the Holy Spirit. 23 If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained.”
and the authority & power to bind and loose in on earth, shall be bound and loose in heaven.
18 And I tell you, you are Peter,[d] and on this rock[e] I will build my church, and the powers of death[f] shall not prevail against it.[g] 19 I will give you the keys of the kingdom of heaven,[h] and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven
And Christ would be with his Church always until the end of time (Matt 28), guided to all Truth. It’s only through this Truth that you can be assured that your bible in inspired and inerrant.

(but you are missing 7 books

)
20
teaching them to observe all that I have commanded you; and lo, I am with you always, to the close of the age.”
What did that Church teach, nearly 300 years before there was a bible? All seven of the Catholic sacraments, including the Eucharist (
more on St. Ignatius here by Pope Benedict).
“They abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again.” Ignatius of Antioch, Epistle to Smyrnaeans, 7,1 (c. A.D. 110).
PnP