1. The mystery of the Son of God, who was made man, and the mystery of the Most Holy Trinity, both pertaining to the innermost substance of Revelation, must be in their authentic truth the source of light for the lives of Christ’s faithful. But because some recent errors undermine these mysteries, the Sacred Congregation for the Doctrine of the Faith has determined to reaffirm and to safeguard the belief in them that has been handed down to us.