I speak to various groups.
When I am in mixed company with different belief backgrounds I adhere to Sola Scriptura and have the scripture interpret scripture as much as possible. In this, the Bible is the authority.
But the Scriptura actually records that The Lord has all authority and He sent His Spirit to the earth who "..will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. He will bring glory to me by taking from what is mine and making it known to you."
By extension, the Holy Spirit is the arbiter of Truth in the earth because He perfectly represents the One who sent Him and He cannot be manipulated by men. However, when the Truth is spoken there will always be a witness of it within the scriptures and within the spirits of men. This is the example of the Bereans: "These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so. Therefore many of them believed..."
God sends a preacher > The preacher preaches > Those who hear it believe > They call on the Lord. The believers, then, will find that the scriptures support the message that was preached. This is outlined in Romans 10
"How then shall they call on Him in whom they have not believed? And how shall they believe in Him of whom they have not heard? And how shall they hear without a preacher? And how shall they preach unless they are sent?"
The process is in revers order so it is: one is sent by the Spirit to preach > The people hear what the Spirit is speaking > The people believe > The people call on the Lord. People were calling on the Lord BEFORE the New Testament was written. Believing the word of God has never been necessarily tied to Bible study: only that a preacher is sent by the Spirit. Certainly, all scripture has been given by 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." These works: reproof, correction, and instruction take place between believers (the mature ministering to the immature); not as if the scriptures do this on their own (how can they believe unless a preacher is sent?). AND, it is these works that bring about the completeness of of the man, not the scriptures themselves. The scriptures become alive to us (changing us) when the word is applied in its appropriate season.
Churches do not recognize "sent ones" very often because they established a more congregational model after Constantine's Roman Church. Although congregations are mentioned in scriptures most believers met in households, households of faith. This was culturally significant: "Sunday/Saturday meetings" were never seen as sufficient for spiritual growth. A life lived in the Body, as the mature watch over the souls of those who are being matured, was the standard. Just as Jesus disciplined those whom the Father gave Him. And just as He gave an account for those whom the Father gave Him, we, too, as elders who watch over the saints, must also give an account to God.
"Remember those who rule over you, who have spoken the word of God to you, whose faith follow, considering the outcome of their conduct. Jesus Christ is the same yesterday, today, and forever. Do not be carried about with various and strange doctrines. For it is good that the heart be established by grace, not with foods which have not profited those who have been occupied with them."
and just a bit later...
"Obey those who rule over you, and be submissive, for they watch out for your souls, as those who must give account. Let them do so with joy and not with grief, for that would be unprofitable for you."
For maturity in Christ, we must receive the one through whom the Word was sent. Reading the scriptures alone will not lead us to maturity.