CCC 190

and so the Creed is divided into three parts: "the first part speaks of the first divine Person and the wonderful work of creation; the next speaks of the second divine Person and the mystery of his redemption of men; the final part speaks of the third divine Person, the origin and source of our sanctification."⁴ Roman Catechism I, 1, 3. These are "the three chapters of our [baptismal] seal".⁵ St. Irenaeus, Dem. ap. 100: SCh 62, 170SCh — Sources Chrétiennes (patristic critical-edition series).