I'm not perfect and some things I don't fully understand.
Well said. I confess the same.
Now, this is not meant as an attack; please follow it through.
If a person’s understanding of the Bible is not complete and whole, then it is possible that that person can err with regard to Biblical teachings. If a person can err with regard to Biblical teachings, then it is possible that that person can hold false beliefs and err in his theology.
Since all human beings are less than perfect and therefore do not hold a complete understanding of something as far-reaching as the Bible, then a human being on his own will therefore to one extent or another, be in error w.r.t. the Bible. This is extra-Biblical support for the concept of the Magisterium. There is either one Church (and one understanding) of the One God and his One Word, or there are many. It is illogical that God’s One Word would speak to all in different ways and have different meanings.
There are some that say that the Holy Spirit has come into them and guides them to the right understanding of the Bible, but, again, it is illogical for One Holy Spirit to guide all Christians to different understanding of the One God and his One Word.