St. Cyprian, Church Father (3rd Century): The Epistles of Cyprian, Epistle LXXII: "Let men of this kind, who are aiders and favourers of heretics, know therefore, first, that those catechumens hold the sound faith and truth of the Church, and advance from the divine camp to do battle with the devil, with a full and sincere acknowledgment of God the Father, and of Christ, and of the Holy Ghost; then, that they certainly are not deprived of the sacrament of baptism who are baptized with the most glorious and greatest baptism of blood".
Epistle LXXII, To Jubaianus, Concerning the Baptism of Heretics: "Let men of this kind, who are aiders and favourers of heretics, know therefore, first, that those catechumens hold the sound faith and truth of the Church, and advance from the divine camp to do battle with the devil, with a full and sincere acknowledgment of God the Father, and of Christ, and of the Holy Ghost; then, that they certainly are not deprived of the sacrament of baptism who are baptized with the most glorious and greatest baptism of blood, concerning which the Lord also said, that He had "another baptism to be baptized with."
The Treatises Of Cyprian, Treatise XI, Exhortation to Martyrdom, Addressed to Fortunatus: "In the baptism of water is received the remission of sins, in the baptism of blood the crown of virtues. This thing is to be embraced and desired, and to be asked for in all the entreaties of our petitions, that we who are God's servants should be also His friends."