St Chromatius was most likely born at Aquileia, and - in any case - grew up there, raised by his mother who had been widowed. He was ordained to the priesthood, and in 387 or 388 after the death of Valerianus, became bishop of Aquileia. He was widely respected and in constant communication with other bishops, especially St Ambrose, St Jerome and St Rufinus. A scholar himself, it was as a result of his active encouragement that these three friends wrote many of their learned works. He was a peacemaker, seeking to bridge the gap between Jerome and Rufinus when they were in dispute. Chromatius was a successful opponent of Arianism, and he gave important support to John Chrysostom, Archbishop of Constantinople, when he was unjustly oppressed. Chromatius was well known as a Bible teacher. In 1969 thirty-eight sermons of his were found and published. Chromatius died in c. 406/407.The following is from his Tractatus XII In Math. III, 13-15 (CCL 9A, 244-246), from Word in Season (2):
Since Jesus was to give a new baptism for the salvation of the human race and the forgiveness of sin, he deigned to be himself baptized first, not in order to put off sins, since he alone had not sinned, but in order to sanctify the waters of baptism that these might wash away the sins of believers. For the waters of baptism could never have cleansed believers of their sins, unless they had first been sanctified by contact with the Lord’s body. He was baptised, therefore, so that we might be washed clean of sins. He was immersed in the water so that we might be cleansed of the filth of sin. He accepted the bath of rebirth so that we might be reborn of water and the Holy Spirit, for as he himself says elsewhere: Unless reborn of water and the Holy Spirit, no one shall enter the kingdom of heaven.
While John did indeed baptise our Lord and Saviour, in a deeper sense he was baptised by Christ, for Christ sanctified the waters, John was sanctified by them; Christ bestowed grace, John received it; John laid aside his sins, Christ forgave them. The reason? John was a man, Christ was God. For it is God’s prerogative to forgive sins, as it is written: Who can forgive sins, except God alone? This is why John says to Christ: I ought to be baptised by you, and do you come to me? For John needed baptism, since he could not be without sin; Christ, however, did not need a baptism, since he had committed no sin.
In this baptism, then, our Lord and Saviour washed away the sins first of John and then of the entire world. It is for this reason that he says: Allow it to be so now. For it is fitting that we should fulfil all justice. The grace of his baptism had been mystically prefigured long ago, when the people were led across the river Jordan into the promised land. Just as at that time a way was opened for the people through the Jordan, with the Lord going on before, so now through the same waters of the river Jordan access has for the first time been given to the heavenly path by which we are led to that blessed land of promise, that is, to possession of the kingdom of heaven. For the people long ago Joshua, son of Nun, was their leader through the Jordan; our leader through baptism to eternal salvation is Jesus Christ the Lord, the only-begotten Son of God, who is blessed forever and ever. Amen.