In 1 John 2:27, the Apostle John teaches us that “the anointing [Holy Spirit] which we have received of him [Christ] abides in us, and we need not that any man teach us: but as the same anointing teaches us of all things, and is truth, and is no lie, and even as it hath taught us, we should abide in him.” In other words, what other teacher do we need besides the Master Teacher Himself, who “abides in us” in the person of the Holy Spirit?
As Christians, we know that we can safely “abide in” or live by whatever the indwelling Christ teaches us, since His teaching is always “the truth” and never a “lie.” Unlike the teaching of men, what Christ teaches us through the Holy Spirit is never mistaken nor misleading. Therefore, you and I can live confidently by whatever Christ says to us through the person of the Holy Spirit who lives within us.
Now, this scriptural teaching should in no way be mistaken as diminishing the importance of the Bible. Instead, it should be understood as the means by which the Bible is to be interpreted. For instance, how would you prefer to learn about a book, from people who had read and studied the book themselves or from the author of the book who actually wrote it? Obviously, you would prefer to learn about the book from its author. Well, what is the best way to learn about the Bible? Is it not from its Author, the Holy Spirit of God who lives within you? Who better to interpret it for you than He who inspired its writing?