How do we know that Christ's sacrifice is effectual for salvation?

The effectiveness of Christ's sacrifice lies in its total sufficiency to atone for sin. As the preacher highlights, when Christ declared, 'It is finished,' He affirmed that the price for sin had been fully paid. This means there is nothing left for believers to do to earn salvation, as it has been accomplished through Christ's perfect obedience and sacrifice. Romans 3:26 underscores this truth, where God's justice and mercy meet in Christ. The promise is that those for whom He died will be justified and accepted by the Father based on His sacrifice alone.