Cyprian of Carthage, Epistle 69.2
The very interrogation used in Baptism also bears witness to the truth. When we ask, "Do you believe in eternal life and the remission of sins through the holy Church?" we acknowledge that remission of sins is given only within the Church; among heretics, where the Church is not, sins cannot be forgiven. Consequently, those who claim heretics can baptize must either alter the interrogation or uphold the truth—unless they are willing to grant the Church to those they say possess Baptism. It is likewise necessary that the baptized person be anointed, so that by receiving the Chrism—that is, the Unction—he may become God's anointed and possess the grace of Christ within himself. Moreover, the Eucharist is the source from which the baptized are anointed with oil upon the sanctified altar. But one who had neither altar nor Church could not sanctify the creature of oil. It follows that spiritual anointing cannot exist among heretics, since it is established that oil cannot be sanctified and the Eucharist cannot be celebrated among them at all. We must know and remember that it is written: "The oil of the sinner shall not anoint my head" (Psalm 141:5), which the Holy Spirit forewarned in the psalms, lest anyone who strays and wanders from the path of truth be anointed among heretics and adversaries of Christ. But what prayer can a sacrilegious and sinful priest offer for the baptized, when it is written: "God does not hear the sinner; but he who worships him and does his will, him he hears" (John 9:31)? For who can give what he himself does not have, or how can one perform spiritual acts who has lost the Holy Spirit? Therefore, the one who comes to the Church in a rude state must be baptized and renewed, so that he may be sanctified inwardly through the Saints, because it is written: "Be holy, for I also am holy, says the Lord" (Leviticus 11:44), so that he who has been led into error and stained outside may also put aside what he incurred when, coming to God and seeking a priest, he fell into the fraud of error and became a sacrilegious person.
Latin
Sed et ipsa interrogatio quae fit in Baptismo testis est veritatis. Nam cum dicimus: Credis in vitam aeternam et remissionem peccatorum per sanctam Ecclesiam? intelligimus remissionem peccatorum nonnisi in Ecclesia dari, apud haereticos autem, ubi Ecclesia non sit, non posse peccata dimitti. Itaque qui haereticos baptizare posse asserunt, aut interrogationem mutent, aut vindicent veritatem, nisi si eis et Ecclesiam tribuunt quos Baptisma habere contendunt. Ungi quoque necesse est eum qui baptizatus sit, ut accepto Chrismate, id est, Unctione, esse unctus Dei et habere in se gratiam Christi possit. Porro autem Eucharistia est unde baptizati unguntur oleo in altari sanctificato. Sanctificare autem non potuit olei creaturam qui nec altare habuit nec Ecclesiam. Unde nec unctio spiritalis apud haereticos potest esse, quando constet oleum sanctificari et Eucharistiam fieri apud illos omnino non posse. Scire autem et meminisse debemus scriptum esse: Oleum peccatoris non ungat caput meum, quod ante in psalmis praemonuit Spiritus sanctus, ne quis exorbitans et a via veritatis exerrans apud haereticos et Christi adversarios ungeretur. Sed et pro baptizato quam precem facere potest sacerdos sacrilegus et peccator, cum scriptum sit: Deus peccatorem non audit; sed qui eum coluerit, et voluntatem ejus fecerit, illum audit. Quis autem potest dare quod ipse non habeat, aut quomodo potest spiritalia agere qui ipse amiserit Spiritum sanctum? Et idcirco baptizandus est et innovandus qui ad Ecclesiam rudis venit, ut intus per Sanctos sanctificetur, quia scriptum est:: Sancti estote, quia et ego sanctus sum, dicit Dominus: ut qui in errorem seductus est et foris tinctus in Baptismo vero et ecclesiastico etiam hoc ipsum deponat quod homo ad Deum veniens, dum sacerdotem quaerit, in sacrilegum fraude erroris incurrit.