22 We have judged, that those also whom they, who had formerly been bishops in the Catholic Church, and afterwards had assumed to themselves the power of clerical ordination, had baptized, are to be regarded as not baptized. And this is observed among us, that whosoever dipped by them come to us are baptized among us as strangers and having obtained nothing, with the only and true baptism of the Catholic Church, and obtain the regeneration of the layer of life. And yet there is a great difference between him who unwillingly and constrained by the necessity of persecution has given way, and him who with a profane will boldly rebels against the Church, or with impious voice blasphemes against the Father and God of Christ and the Creator of the whole world. And Stephen is not ashamed to assert and to say that remission of sins can be granted by those who are themselves set fast in all kinds of sins, as if in the house of death there could be the layer of salvation.
Source: The Epistles of Cyprian (New Advent)