Bible study and Bible knowledge does not make you a child of God. Church membership and being religious, having a baptismal certificate to prove that you were baptized, that does not make you a child of God. Even if you pray in tongues it does not make you a child of God, or if you prophesy, or preach or a show much charity.
The question is: Are you a disciple of Jesus Christ? Do you have the nature of Jesus? Do you show the fruit of being a child of God? Do you love Jesus Christ and do you love your neighbor? Many profess to be Christians but they are not disciples, are not born again. They love themselves they do not love Jesus and they do not love their neighbor. They love the world and the things of the world but they are religious, yet they call themselves Christians. We need to be disciples of Jesus Christ, followers of Jesus, and we need to show fruit of repentance, fruit of being born again, fruit of being a children of God. Fruit of repentance is not just to admit that you are a sinner and then continue sinning. No, you turn away from your previous lifestyle of sin and self gratification; you turn away from being worldly and self-centered and you go after Jesus Christ, you obey His words, His commands. You truly repent and you become a new creature inside, a child of God who does the will of God. You turn away from sin and you live holy and righteous, you obey Jesus and you are baptized in water, for the washing off of your sin and after that you live a life that is dedicated to Jesus Christ, you are separated unto Him. You are not like the world. You do not follow after your own desires and after the things of the world, you seek the will of God. You become a disciple; you seek the presence of Jesus, His Holy Spirit to dwell in you and to guide you every step of the way, so that you can do the will of God. You live to please Him, not to please yourself. You do not try to impress other people. You are only interested in being pleasing to God. Being a child of God, is being a disciple of Jesus Christ and nothing less. Being a child of God means being of Jesus, belonging to Jesus, and not of the world or of the church.
A disciple of Jesus Christ belongs to Him, he is of the kingdom of God. Have you become a disciple of Jesus Christ? Are you of Jesus Christ?
May Jesus bless you.