Every disciple of the Lord Jesus Christ is a believer, but not every believer is a disciple. The biblical portrait of a true disciple is someone who lives in obedience to the Word of God, and not someone who simply believes on Him for salvation. Many many people have believed on him for salvation, but doing so does not make you a disciple of the Lord Jesus Christ.
It must also be understood that true biblical discipleship is not solely the academic pursuit of knowledge alone. We know from 1 Corinthians 8:1, that “knowledge puffeth up.” Having knowledge of the word of God without living out the principles of the word of God can give you a “big head.” There must be a period in your relationship with the Lord, that you go through, where you “learn of Him.” But a true disciple is both a learner and a follower of the Lord Jesus Christ. True Disciples learn of Jesus through the reading and study of God’s Word, but then, you must follow him by living in obedience to what you have learned of Him.
But he said, Yea rather, blessed are they that hear the word of God, and keep it.