Scripture alone is sufficient, your interpretation alone may not be.
The Bible is infallible truth about God
First off, whatever people say, think, imagine, see, hear, argue, or write is never going to be as valid as the Word of God. The greatest of philosophical arguments, the realest experiences, or most ancient traditions can never be equal to Scripture in terms of value and authority. If the Bible says that Jesus is God, and you try to reason against it, feel that he isn’t, or show that everyone in history thinks otherwise, the Bible is still right. This article is not about the Authority of Scripture, for Scripture has the utmost Authority. The reformers came up with the phrase “Sola Scriptura” or Scripture Alone. And indeed I wholly agree, Scripture alone is fully authoritative truth, however, we must be careful to not confuse ourselves and think that truth equals “the way I feel or think about Scripture alone.” You ought to read the Bible daily. And only trust the Bible as the highest authority, but don’t read the Bible alone in a vacuum, with only your head to rely upon. Don’t trust in your head alone, seek out wise Christian council, for the Bible was given to a community.
Sometime the Bible can be hard to understand
First off, let us realize that the Bible is a hard book. Before you hang me, allow me to remind you that I didn’t make this up. No, it was actually the Bible that says the Bible is hard to understand. “Our beloved brother Paul also wrote to you according to the wisdom given him, as he does in all his letters… There are some things in them that are hard to understand.” (2 Peter 3:15-16). Peter is talking about Apostle Paul’s epistles, which Peter confirms are Scripture in this same verse, and Peter states that some Scriptures are hard to understand. If Peter, who wrote a few books of the Bible, says the Bible can be hard, we should agree. Though lets note the problem is not with Scripture, the problem is with our brains. It is not Scripture that needs changing, but our brains and hearts.
The Bible needs a guide to be understood properly
Because it can be hard to understand Scripture, we need a guide. Jesus reveals that this guide is the Holy Spirit (John 14:26), he inspired the human authors of Scripture, and he reveals it to us today. This can happen in a few different ways, that often work together. First, our hearts and minds are supernaturally changed from a carnal way of thinking so that we can believe the Bible. Second, since God used grammar and cultural context to write His word, He reveals it to us when we read with the rules He wrote it with. Third, God appointed human guides, called pastors, and gave them the gift of wisdom and knowledge to teach and equip the church (1 Cor 12:8; Ephesians 4:11-13). This doesn’t mean the pastor has the authority in himself, nor is he some kind of intermediary. There are many good pastors who can be wrong, and many who are so wrong they should not be pastors. Yet if one whom God appointed can be wrong, are you less likely to be wrong if you go completely alone? If you try to know the Bible completely apart from all those whom God appointed as pastors and teachers, you are doing it differently from the way God intended and instructed.
Books written by Pastors-scholars are the means of illumination
There are bad books that twist and deny scripture. There are also good books, written by pastors who love Jesus and the Bible. Pastors who are called to teach, and moved by the Spirit to teach. These books are filled with hundreds of Bible citations. They contain solid Christian explanations of hard to understand passages. They are basically a sermon in written form. God ordained that sermons should be central to spreading the message of Christianity, yet clearly not everyone is called to preach and teach (James 3:1; So if you alone “teach” yourself that could be dangerous. I don’t teach myself or others alone, but always see if there is a consensus between solid Bible teachers on the issue.) Books or articles are like written sermons. Again, not everyone should write, but when a pastor whom God appoints writes, then God’s spirit moves through that writing as a method of revealing Scripture to you. If you fully refuse to read Christian literature it is NOT that you trust the Bible instead of “those books.” No, the alternative is that you think you know everything and ONLY trust your personal interpretation.