How do we know Christ's work for us is sufficient?

According to Romans 5:19, Christ’s obedience ensures that many are made righteous. His work signifies not only a covering for our sins but also a new spiritual birth in those who believe. By faith, we are justified and made heirs to eternal life (Titus 3:5). His dual role as both our righteousness and our sanctification (1 Corinthians 1:30) confirms that His work is comprehensive and entirely sufficient for our salvation, addressing both legal justification and our ongoing spiritual renewal.