Why is it necessary to believe in the heart when confessing Christ?

Romans 10:10 emphasizes the necessity of belief in the heart for salvation, stating that with the heart one believes unto righteousness. This indicates that true confession arises from a heartfelt conviction about who Christ is and what He has accomplished for sinners. An outward confession without inward belief is mere hypocrisy; hence, valid salvation and confession must stem from a genuine transformation wrought by the Spirit of God. This faith in the heart is the foundation for authentic expression of faith through words and actions.