Before His ascension, Jesus commissioned His disciples TO TEACH THE NATIONS TO OBEY ALL His commands (Matthew 28:18-20). The word "teach" means: To disciple or make a pupil. Thus, the Church has the mandate to teach its members how to obey the Word of God.
Teaching in the church is vitally important. I like what Billy Graham said. He said: “Church is not for pretenders and performers. The church is aplace for pastors to preach principles of faith in order to prepare believers to face the storms of life on the stage of an unbelieving world.”
Far too many people try to navigate through their Christian life with a very limited knowledge of the Bible. They lean so heavily on the teachings of their ancestors and former ministers they never search the Scriptures for themselves, which leaves them vulnerable to false doctrines and erroneous ideologies.
This discipleship program is of little value to a lost man. The Bible says the gospel is hidden to him (2Co 4:3). There are drug addicts that believe they are saved because they gave their heart to God at an early age.
There isn’t much we can teach them until they fully surrender their lives to God. You cannot put a chimney on a house when you have yet to pour a foundation and build the floors and walls.