The Bible is the only authority we need. It is the source of the revelation of Yahuwah’s truth, and it contains everything we need in regard to our faith in Jesus Christ. It is clear to me that those who wrote the Bible were moved and inspired by the Holy Spirit to articulate in writing what we need. The Bible is perfect and infallible within its original languages.
Paul writes, “All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work” (2 Timothy 3:16-17 NKJV).
Peter writes, “…for prophecy never came by the will of man, but holy men of God spoke as they were moved by the Holy Spirit” (2 Peter 1:21 NKJV).
Everything humans teach and do in regard to our faith in Christ should be tested against the Bible and what it says. We should always be like the Bereans that searched the scripture to make sure what is being taught is true (Acts 17:11).
No teaching or tradition of fallible man will ever be superior to the Bible, and if fallible man contradicts the clear doctrine of scripture… that man is wrong. That is one reason for the Reformation and the call of sola scriptura! Sadly the Roman Catholic Church was corrupted and still dwells in the darkness of false doctrine.
Below is an excellent Q & A with John Piper in regard to the sufficient authority of the Bible.