2 You can not hear His words, while you do not know yourself; and if you keep His judgments while your understanding is aloof from Him, who will give you your reward? Who will keep for you your recompense? You were baptised in His Name; confess His Name! In the Persons and in the naming, Father and Son and Holy Spirit, three Names and Persons, these three shall be a wall to you, against divisions and wranglings. Doubt not of the truth, lest you perish through the truth. You were baptised from the water; you have put on Christ in His naming; the seat of the Lord is on your person and His stamp on your forehead. See that you become not another's, for other Lord have you none. One is He Who formed us in His mercy; one is He Who redeemed us on His cross. He it is Who guides our life; He it is Who has power over our feebleness; He it is Who brings to pass our Resurrection. He rewards us according to our works. Blessed is he that confesses Him, and hears and keeps His commandments! You, O man, are a son of God Who is high over all. See that you vex not by your works the Father Who is good and gracious.
Source: On Admonition and Repentance (New Advent)