9 I suppose, brethren, that this is known in the Church, and that what we are saying is manifest by daily examples; but let us consider these things in the case of our fathers before us, how they also had these four kinds. Of the good, good; Ananias baptized Paul. How of the evil, evil? The apostle declares that there were certain preachers of the gospel, who, he says, did not use to preach the gospel with a pure motive, whom, however, he tolerates in the Christian society, saying, “What then, notwithstanding every way, whether by occasion or in truth, Christ is preached, and in this I rejoice.” Was he therefore malevolent, and did he rejoice in another's evil?
No, but rejoiced because through evil men the truth was preached, and by the mouths of evil men Christ was preached. If these men baptized any persons like themselves, evil men baptized evil men: if they baptized such as the Lord admonishes, when He says, “Whatsoever they bid you, do; but do not ye after their works,” they were evil men that were baptizing good. Good men baptized evil men, as Simon the sorcerer was baptized by Philip, a holy man. Therefore these four sorts, my brethren, are known.
See, I repeat them again, hold them, count them, think upon them; guard against what is evil; keep what is good. Good men are born of good, when holy men are baptized by holy; evil men are born of evil, when both they that baptize and they that are baptized live unrighteously and ungodly; good men are born of evil, when they are evil that baptize, and they good that are baptized; evil men are born of good, when they are good that baptize, and they evil that are baptized.
Source: Tractates on the Gospel of John (New Advent)