How do we know that the process of sanctification is true?

The reality of sanctification is underscored by the presence of the Holy Spirit in believers. Romans 7 illustrates the internal struggle between the old sinful nature and the new belief in Christ, demonstrating that true believers recognize their inability to fulfill the Law on their own and cry out for divine help. This inward struggle indicates that sanctification is not solely an act of will but a work of God through His Spirit. Additionally, passages like Ephesians 1:4-5 indicate that believers are chosen and predestined for holiness, affirming that the transformative work of sanctification is an essential part of salvation.