All Saints' (8) Gregory Nazianzen

"The Word recognizes three Births for us; namely, the natural birth, that of Baptism, and that of the Resurrection. Of these the first is by night, and is servile, and involves passion; but the second is by day, and is destructive of passion, cutting off all the veil that is derived from birth, and leading on to the higher life; and the third is more terrible and shorter, bringing together in a moment all mankind to stand before its Creator and to give an account of its service and conversation here; whether it has followed the flesh, or whether it has mounted up with the spirit and worshipped the grace of its new creation. My Lord Jesus Christ has showed that He honoured all these births in His own Person; the first, by that first and quickening Inbreathing; the second by His Incarnation and the Baptism wherewith He Himself was baptized; and the third by the Resurrection of which He was the Firstfruits; condescending, as He became the Firstborn among many brethren, so also to become the Firstborn from the dead.
Concerning two of these births, the first and the last, we have not to speak on the present occasion. Let us discourse upon the second, which is now necessary for us, and which gives its name to the Feast of the Lights. Illumination is the splendour of souls, the conversion of the life, the question put to the Godward conscience. 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 of light, the dissolution of darkness. It is the carriage to God, the dying with Christ, the perfecting of the mind, the bulwark of Faith, the key of the Kingdom of heaven, the change of life, the removal of slavery, the loosing of chains, the remodelling 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, as being more holy than any other illumination which we possess."

--from "The Oration on Holy Baptism," preached in Constantinople on January 6, 381.