13 But, moreover, in respect of some calling those who have obtained the peace of Christ by the saving water and by legitimate faith, not Christians, but Clinics, I do not find whence they take up this name, unless perhaps, having read more, and of a more recondite kind, they have taken these Clinics from Hippocrates or Soranus. For I, who know of a Clinic in the Gospel, know that to that paralytic and infirm man, who lay on his bed during the long course of his life, his infirmity presented no obstacle to his attainment in the fullest degree of heavenly strength.
Nor was he only raised from his bed by the divine indulgence, but he also took up his bed itself with his restored and increased strength. And therefore, as far as it is allowed me by faith to conceive and to think, this is my opinion, that any one should be esteemed a legitimate Christian, who by the law and right of faith shall have obtained the grace of God in the Church. Or if any one think that those have gained nothing by having only been sprinkled with the saving water, but that they are still empty and void, let them not be deceived, so as if they escape the evil of their sickness, and get well, they should seek to be baptized. But if they cannot be baptized who have already been sanctified by ecclesiastical baptism, why are they offended in respect of their faith and the mercy of the Lord?
Or have they obtained indeed the divine favour, but in a shorter and more limited measure of the divine gift and of the Holy Spirit, so as indeed to be esteemed Christians, but yet not to be counted equal with others?
Source: The Epistles of Cyprian (New Advent)