How do we know regeneration is true for Christians?

Regeneration is confirmed through the transformative experience of a believer's desires and actions. In Romans 7, Paul expresses a profound internal conflict whereby he delights in the law of God according to his inward man but also experiences the pull of sin through his flesh (Romans 7:22-23). This duality indicates that a genuine work of grace has occurred within him, showcasing a heart that desires to please God, despite the struggle with sinful tendencies. The presence of this conflict and the believer's abhorrence of sin are consistent with the reality of regeneration, as it produces a new nature that is at odds with the remnants of the old sinful self. As Paul distinguishes between his renewed self and the sin that dwells within, it underscores the truth of regeneration through the grace of God.