God is eternal and has always existed in 3 forms: God the Father, God the Son and God the Holy Spirit. Each is distinct in person but equal as “God”
Man was created by God, in His image. Since we were created in His image, we also have 3 parts: body, soul and spirit.
When man sinned by disobeying God, his spirit died and he became condemned to eternal death in a literal hell. “For the wages of sin is death…” Romans 6:23
God the Son came to earth as an infant, being born of a virgin, in order to fulfill prophecies in the Bible foretold about Him and to voluntarily die in order to pay the penalty for those willing to trust in Him. “For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.” Romans 6:23
For man to receive this gift of salvation, he needs to confess with his mouth that he believes Jesus died in his place in payment for the penalty of his sins. He can ask God to forgive him and allow God to be the lord of his life. Man is then justified and made righteous by the blood payment of Jesus who lived a sinless life. The Holy Spirit immediately enters into the previously dead spirit of man and allows continuous communion with God.
Man then begins the process of transforming his soul; which is made up of his mind, will and emotions. This process is called sanctification or making Him Lord of your life. It means man is becoming more like Christ and giving the power of decision over to God instead of himself. This is accomplished through discipleship and mentoring by a mature Christian. “It is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself up for me.” Galatians 2:20