The scribes and Pharisees proudly preserved the OT scriptures, yet were also devoted to their own teachings and traditions, and were rebuked for it.
They were rebuked when their teachings and traditions neglected the "weightier matters of the law" but he did not rebuke their teachings and traditions as such: "you should have practiced the latter, without neglecting the former."(Matthew 23:23) Nor did he deny their authority to sit in Moses' seat, insisting rather that "you must obey them" even when their practice does not fit what they preach (Matthew 23:3). He transferred their authority to the Apostles, giving the Apostles the power of binding and loosing which had previously been held by the Sanhedrin (Matthew 16:19, 18:18). The Apostles in turn passed on their authority through the laying of hands (Acts 6:6, 13:3, 1 Timothy 4:14, 2 Timothy 1:6; also see the quotes I posted in #533 on the Apostolic succession). Without this succession of apostolic authority, where do Christians have any divine authorization for our mission? Would we not be preaching a merely human tradition if today's Church has no divine authorization descended from the Apostles?
But beyond the issue of apostolic authority, there is the issue of historical attestation: how do we know which books belong in the Bible, if we dismiss as unreliable witnesses our only witnesses to their apostolic authorship, as some posts in this thread have done with respect to their attestation to the practice of the early church?