Tertullian

“ Warning, accordingly, the disciples to omit all first principles, and strive rather after perfection, and not lay again the foundations of repentance from the works of the dead, he says: “For impossible it is that they who have once been illuminated, and have tasted the heavenly gift, and have participated in the Holy Spirit, and have tasted the word of God and found it sweet, when they shall—their age already setting—have fallen away, should be again recalled unto repentance, crucifying again for themselves the Son of God, and dishonouring Him.” ”

“ I wish, however, redundantly to superadd the testimony likewise of one particular comrade of the apostles,— (a testimony) aptly suited for confirming, by most proximate right, the discipline of his masters. For there is extant withal an Epistle to the Hebrews under the name of Barnabas—a man sufficiently accredited by God, as being one whom Paul has stationed next to himself in the uninterrupted observance of abstinence: “Or else, I alone and Barnabas, have not we the power of working?” ”

“ It was with a reference, in short, to this species of discipline that the caution was taken in the case of the leper: “But if the speckled appearance shall have become efflorescent over the skin, and shall have covered the whole skin from the head even unto the feet through all the visible surface, then the priest, when he shall have seen, shall utterly cleanse him: since he hath wholly turned into white he is clean. ”