Biblical explanation
Jesus introduced this teaching in His conversation with Nicodemus: "Except a man be born again, he cannot see the kingdom of God" (John 3:3). Nicodemus initially interpreted the statement literally, but Jesus explained that He was speaking about spiritual birth. "Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God" (John 3:5). The Holy Spirit produces this new life. Titus 3:5 describes salvation as involving "the washing of regeneration, and renewing of the Holy Ghost." Peter similarly says believers are "born again" through the living Word of God (1 Peter 1:23). The new birth changes the direction of a person's life. Paul describes the result as becoming a "new creature" (2 Corinthians 5:17). The new birth therefore does not mean becoming physically different. It means receiving a new spiritual orientation through God's grace and the work of the Holy Spirit.
Key takeaway
Salvation is entirely by grace through faith in Christ. His atoning sacrifice, heavenly ministry, and intercession are the foundation of assurance; obedience, Sabbath faithfulness, and loving service are the fruit of a redeemed life, never a way to purchase acceptance with God.