What does it mean to have the blood of Christ applied to my heart?

The application of Christ's blood to the believer's heart refers to the transformative work of the Holy Spirit in the new birth. Just as the blood of the Passover lamb had to be visibly applied for protection, the blood of Christ must be applied to the believer's heart for purification and new life. This is accomplished through faith, which is a gift from God. When Christ's blood is applied, it sanctifies and purifies, signifying that the believer has been made righteous and is now part of God's family.