Translated by Ch. Browne and J. Swallow.
The Oration on the Holy Lights was preached on the Festival of the Epiphany 381, and was followed the next day by that on Baptism. In the Eastern Church this Festival is regarded as more particularly the commemoration of our Lord's Baptism, and is accordingly one of the great days for the solemn ministration of the Sacrament. It is generally called Theophania, and the Gospel in the Liturgy is S. Matthew iii. 13-17. The Sunday in the Octave is called meta ta phota (After The Lights), pointing to a time when the Feast was known as the "Holy Lights," as seems to have been the case in S. Gregory's day. This name is derived from Baptism, which was often in ancient days called Illumination, in reference to which name (derived from the spiritual grace of the Sacrament) lighted torches or candles were carried by the neophytes. It would appear that the solemnites of the Festival lasted two days, of which the second was devoted to the solemn conferring of the Sacrament. Accordingly we find two Orations belonging to the Festival. In the first, delivered on the Day itself he dwells more especially on the Feast and the Mystery of our Lord's Baptism therein commemorated; and proceeds to speak of the different kinds of Baptism, of which he enumerates Five, viz.:—
1. The figurative Baptism of Israel by Moses in the cloud and in the Sea.
2. The preparatory Baptism of repentance ministered by S. John the Baptist.
3. The spiritual Baptism of water and the Holy Ghost given us by our Lord.
4. The glorious Baptism of Martyrdom.
5. The painful Baptism of Penance.
In speaking of this last he takes occasion to refute the extreme rigorism of the followers of Novatus, who denied absolution to certain classes of sins committed after Baptism.
In the second Oration, delivered next day, he dwells on the Sacrament of Baptism and its spiritual effects; and takes occasion to reprove the then still prevalent practice of deferring Baptism till the near approach of death. He likewise dwells on the truth that the validity and spiritual effect of the Sacrament is wholly independent of the rank or worthiness of the Priest who may minister it; and he concludes with a sketch of the obligations which its reception involves, with a very valuable exposition of the Creed, and of the Ceremonies which accompanied the administration of the Sacrament.
Reference address : https://www.elpenor.org/gregory-nazianzen/holy-lights.asp