The first verse of The Book of Acts (emphasis mine): "The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach," This is Luke speaking. The Book of Acts and Luke's Gospel were originally written and released as one book. But that's beside the point.
How often do we regard Jesus as our teacher? He is a rabbi, after all.
If we already know everything, then this aspect of His, uh, job description (?) would necessarily be overlooked. This is called pride, by the way. There's no way we can learn from God if we're in pride, it just won't happen.
"If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and ubraideth not; and it shall be given him. But let him ask in faith, nothing wavering. For he that wavereth is like a wave of the sea driven with the wind and tossed. For let not that man (or woman) think that [they] shall receive anything of the Lord." (James 1:5-7, emphasis mine)
"Study to shew thyself approved unto God" (2 Timothy 2:15) Paul writes to Timothy. A young man from Lystra, he became a protégé of Paul's, effectively starting his own church for which Paul provides counsel and encouragement in two different missives. It's not an easy thing, teaching others. One must not only be called, but also equipped to be able to take ethereal ideas and concepts and not only understand them inside and out, but also be able to (one) put them in their own words (vital). And then (two) be able to express the same to a bevy of students of every stripe and station. "Let him that is taught in the word communicate unto him that teacheth in all good things." (Galatians 6:6) This can't happen unless the teacher is a good one. And in order to become a good teacher, one must be taught of God.
Someone who is self-taught. It can be about anything. I'm writing here about matters spiritual, Christian. Not just religious. Jesus expresses his willingness to teach anyone: "Come unto me, all ye that labor and are heavy laden, and I will give you rest. Take my yoke upon you, and learn of me (learn from me); for I am meek and lowly in heart: and ye shall find rest unto your souls." (Matthew 11:28-29, emphasis mine) But what kind of knowledge are we talking about here? Certainly, the knowledge that Jesus imparts is not the "knowledge" that "puffeth up" (1 Corinthians 8:1). Could it be the same that Paul is referring to in his letter to the Colossians? (1:10, emphasis mine) "That ye might walk worthy of the Lord unto all pleasing, being fruitful in every good work, and increasing in the knowledge of God." Sounds about right. Notice the preceding lines in the verse, that speak of "walk[ing] worthy of the Lord", "pleasing" Him, and being "fruitful in every good work." Knowledge that is practical, purposeful, useful.
"And the Lord answered me, and said, Write the vision, and make it plain upon tables, that he may run that readeth it." (Habakkuk 2:2) That he (and she) may run... That it will cause us to be more like Him. And anytime we would submit to a Christian teacher, the knowledge disseminated must inspire one to become more like Jesus. It must be alive. No two ways (or one, for that matter) around it. "The words that I speak unto you, they are spirit, and they are life." (John 6:63) It's understandable, if there should be a paucity of quality teachers, how one would take the route of autodidact and seek to learn from God Himself. Though, don't confuse the willingness to learn from God alone, for an irrational (read disobedient) lone-wolf approach to biblical studies.
Acts 8 (27-40) speaks of an Ethiopian returning to his homeland from Jerusalem. "Then the Spirit said unto Philip, Go near, and join thyself to this chariot. And Philip ran thither to him, and heard him read the prophet Esaias, and said, Understandest thou what thou readest? And he said, how can I, except some man should guide me? And he desired Philip that he would come up and sit with him." (verses 29-31, emphasis mine) The same Philip to whom Jesus said months prior: "Have I been so long time with you, and yet hast thou not known me?" (John 14:10) The Old Testament passage the Ethiopian was having trouble understanding was from Isaiah and spoke prophetically of Jesus. And the only way Philip was able to expound on the truth contained therein was because he knew Jesus. Between the time Jesus expressed His dismay and alarm at Philip's personal ignorance and the passage in Acts, Philip gained a deep understanding of who Jesus is (their relationship was ratified, so to speak—see Galatians 4:19). So much so, that he was able to introduce the Ethiopian man to Him.
We all start that way. We go to church. We read the Bible. We participate. But until we avail ourselves of Jesus through humility, do we ever gain the insight needed to actually teach others what God Himself has taught us.
From this: "I will instruct thee and teach thee in the way which thou shalt go: I will guide thee with mine eye." (Psalm 32:8) This is God speaking.
To this: "Then will I teach transgressors thy ways; and sinners shall be converted unto thee." (Psalm 51:13) And that's David (one of His star pupils; see Acts 13:22).
And if you find yourself "held back", it's for a good reason. God is teaching you!