Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 36

Chapter 36.—69.  Eucratius of Theni 1725 said:  "Our God and Lord Jesus Christ, teaching the apostles with His own mouth, fully laid down our faith, and the grace of baptism, and the rule of the law of the Church, saying, ‘Go ye, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.’ 1726   Therefore the false and unrighteous baptism of heretics is to be repudiated by us, and contradicted with all solemnity of witness, seeing that from their mouth issues not life, but poison, not heavenly grace, but blaspheming of the Trinity.  And so it is plain that heretics coming to the Church ought to be baptized with perfect and Catholic baptism, that, being purified from the blasphemy of their presumption, they may be reformed by the grace of the Holy Spirit."  1727

70.  Clearly, if the baptism is not consecrated in the name of the Father, and of the Son, and of the Holy Ghost, it should be considered to be of the heretics, and repudiated as unrighteous by us with all solemnity of witness; but if we discern this name in it, we do better to distinguish the words of the gospel from heretical error, and approve what is sound in them, correcting what is faulty.

Footnotes

Theni was in ecclesiastical province of Byzacene.  A Eucratius occurs in Cypr. Ep. ii.

Matt. xxviii. 19.

Conc. Carth. sec. 29.