Proverbs 12:1 (NKJV)
One thing that is clear, and often very obvious, is that no one knows everything. While some people do have a lot of knowledge, wisdom, and understanding in general, and even in some specific areas, no person has all knowledge, wisdom, or understanding about everything. But, if all the knowledge, wisdom, and understanding of several people would be combined, then there is a greater amount of all of those things. This is why it is important for us to be willing to listen to other people, and to be open to correction.
While it is true of knowledge in general, it is also true that no one knows everything about the Bible and the things of God. We may have learned a great deal about God and some things in the Bible, but there is still so much that all of us do not know, and this is why we always need to remain teachable and open to others giving us instruction, advice, and correction. If we are not willing to listen to others, then we will never really learn, and we may continue to do or believe things that are wrong.
It is better for someone to tell us what is true than for us to continue doing something wrong or believing the wrong things. If we are not open to correction, if we somehow think we know everything and no one can correct us, then we are in a sad condition and we are deceived. We need to be open to advice and correction, about how we do things and especially about what we believe the Bible teaches, to be sure we continue moving forward in the things of God, rather than persist in doing things our way and continuing to believe what we believe, and end up having problems.