With the words, "You must be born again," the Lord Jesus Christ clearly established the necessity of the new birth. But what does regeneration actually do in a person? Should we expect the new birth to produce extensive changes in the soul or minor ones? Is the Bible's doctrine of regeneration large or small? This booklet discusses five of regeneration's most important practical implications: it highlights the free, uncaused, and sovereign character of God's saving grace; it sets a high standard for personal holiness; it explains why true believers will always persevere in their faith; it helps Christians understand their union with Christ; and it answers a common objection to the Reformed understanding of salvation.