Our Lord Jesus gave us a command.
"Go ye therefore, and teach all nations... Teaching them to...." (Matthew 28:19-20, KJV)
The word 'teach' is mentioned by the Lord twice in the above scripture. They have their places in Christianity. Teaching has been replaced to Preaching to the detriment of lacking of knowledge. Teaching will open the door of knowledge that will lead us to the implementation of the promises. (Galatians 5:6).
The Bible also says,
"Now I say, That the heir, as long as he is a child, differeth nothing from a servant, though he be lord of all; But is under tutors and governors...that we might receive the adoption of sons." (Galatians 4:1-5, KJV)
"But is under tutors and governors . . ." This statement is making reference to teachers and not preachers. Teaching will give transformation while preaching will be giving conformation.
The Bible says,
"And be not conformed to this world: but be ye transformed by the renewing of your mind..." (Romans 12:2, KJV)
It is teaching and the absorption of Word that can bring transformation.
"Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth." (2 Timothy 2:15, KJV)
God wants us to be equipped with knowledge and understanding.
"My people are destroyed for lack of knowledge..." (Hosea 4:6, KJV)
It is our obligation as Christians to rise to maturity and also in the unity of the faith.
"For the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God..." (Ephesians 4:12-13, NKJV)
The Lord Jesus gave us another instruction before leaving the earth saying,
"...he who believes in Me, the works that I do he will do also..." (John 14:12, NKJV)
Knowledge and understanding are needed to do His works.