"Let us discourse upon the second birth in baptism, which is necessary for us, and which gives its name to the Feast of the Lights (Epiphany). Illumination is the splendor of souls, the conversion of the life, the questions put to the good conscience toward God (1Pt 3:21). It is the aid to our weakness, the renunciation of the flesh, the following of the Spirit, the fellowship of the Word, the improvement of the creature, the overwhelming of sin, the participation in light, the dissolution of darkness. It is conveyance to God, dying with Christ, the perfecting of the mind, the rampart of faith, the key of the kingdom of heaven, the change of life, the manumission of slavery, the loosing of chains, the remodeling of the whole man. Why should I go into further detail? Illumination is the greatest and most magnificent of the gifts of God. For just as we speak of the Holy of Holies, and the Song of Songs, as more comprehensive and more excellent than others, so is this called illumination because it is more holy than any other illumination which we possess.
"As Christ the giver of it is called by many various names, so too is this gift, whether it is from the exceeding joy of its nature (as those who are very fond of a thing take pleasure in using its name), or that the great variety of its benefits has reacted for us upon its names. We call it, the gift, the grace, baptism, anointment, illumination and, the clothing of immortality, the font of regeneration, the seal, and everything that is honorable. We call it the gift, because it is given to us in return for nothing on our part; grace, because it is conferred even on debtors; baptism, because sin is buried with it in the water; anointment, because it is priestly and royal. It is called illumination, because of its splendor; Clothing, because it hides our shame; the font, because it washes us; the seal because it preserves us, and is moreover the indication of the Lord's dominion. In it the heavens rejoice. It is glorified by angels, because of its related splendor. It is the image of the heavenly bliss. We long indeed to sing out its praises, but we cannot worthily do so."
Gregory Nazianzus, Theological Oration, 40.3-4
Almighty and most merciful God and Father, we thank and praise You that You graciously preserve and enlarge Your family and have granted us the new birth in Holy Baptism and made us members of Your Son, our Lord Jesus Christ, and heirs of Your heavenly kingdom. We humbly implore You that, since we have become Your children, You would keep us in our baptismal grace, that according to Your good pleasure we may faithfully lead a godly life to the praise and honor of Your holy name and finally, with all Your saints, obtain the promised inheritance in heaven; through Jesus Christ, our Lord. Amen.