“Remember, then, that you received a spiritual seal, the spirit of wisdom and understanding, the spirit of knowledge and reverence, the spirit of holy fear. Keep safe what you received. God the Father sealed you, Christ the Lord strengthened you and sent the Spirit into your hearts as the pledge of what is to come, as you learned in the reading from the Apostle.” (St. Ambrose of Milan, Bishop and Doctor of the Church, from a treatise On the Mysteries)