Gregory of Nazianzus — as excerpted in the Catena Aurea on Luke 3:3-6

“(Orat. 39.) To speak now of the difference of baptisms. Moses indeed baptized, but in the water, the cloud, and the sea, but this was done figuratively. John also baptized, not indeed according to the Jewish rite, (for he baptized not only with water,) but also for the remission of sins, yet not altogether spiritually, (for he adds not, in the Spirit.) Jesus baptizes but with the Spirit, and this is perfect baptism. There is also a fourth baptism, namely by martyrdom and blood, by which also Christ Himself was baptized, and which is so far more glorious than the others, as it is not sullied by repeated acts of defilement. There is also a fifth, the most weary, according to which David every night washed his bed and his couch with tears. It follows, As it is written in the book of Esaias the Prophet, The voice of one crying in the wilderness. (Is. 40:3.)”