Edited from a variety of translations (mentioned in the preface) by H. R. Percival
But who can give what himself hath not? or how can he perform spiritual acts, who hath himself lost the Holy Spirit? Wherefore he is to be baptized and received, who comes uninitiated to the Church, that within he may be hallowed through the holy; for it is written, "Be ye holy, for I am holy, saith the Lord." So that he who has been seduced into error and washed without should, in the true Baptism of the Church, put off this very thing also; that he, a man coming to God, while seeking for a priest, fell, through the deceit of error, upon one profane. But to acknowledge any case where they have baptized, is to approve the baptism of heretics and schismatics.
For neither can part of what they do be void and part avail. If he could baptize, he could also give the Holy Ghost. But if he cannot give the Holy Ghost because, being set without, he is not with the Holy Ghost, neither can he baptize any that cometh: for that there is both one Baptism, and one Holy Ghost, and one Church, founded by Christ the Lord upon Peter, through an original and principle of unity; so it results, that since all among them is void and false, nothing that they have done ought to be approved by us. For what can be ratified and confirmed by God, which they do whom the Lord calls his enemies and adversaries, propounding in his Gospel, "He that is not with me, is against me; and he that gathereth not with me, scattereth." And the blessed Apostle John also, keeping the commandments and precepts of the Lord, has written in his Epistle, "Ye have heard that Antichrist shall come; even now are there many Antichrists, whereby we know that it is the last time. They went out from us, but were not of us; for if they had been of us, they would no doubt have continued with us." Whence we, too, ought to infer and consider, whether they who are the adversaries of the Lord, and are called Antichrists, can give the grace of Christ. Wherefore we who are with the Lord, and who hold the unity of the Lord, and according to this vouchsafement administer his priesthood in the Church, ought to repudiate and reject and account as profane, whatever his adversaries and Antichrists do; and to those who, coming from error and wickedness, acknowledge the true faith of the one Church, we should impart the reality of unity and faith by all the sacraments of Divine grace.
We bid you, dearest brethren, ever heartily farewell.
Reference address : https://www.elpenor.org/ecumenical-councils/carthage-257.asp?pg=5