Adolf von Harnack

“ Though he is wanting in moderation and in luminous warmth, his tones are by no means always harsh; and as an author he ever aspired with longing after humility and love and patience, though his whole life was lived in the atmosphere of conflict. ”

“ The same Tertullian who had fortified the Catholic church against Gnosticism was none the less anxious to protect it from becoming a political organization. Being unable to reconcile incompatibles, he broke with the church and became the most powerful representative of Montanism in the West.
Although Tertullian's extant works are both numerous and copious, our knowledge of his life is very vague. He cannot have been born much later than about 150. His activity as a jurist in Rome must fall within the period of Commodus ”

“ The Apologeticus, which in the 3d century was translated into Greek, is the weightiest work in defence of Christianity of the first two centuries. Respecting its relation to the Octavius of Minucius Felix much has been written; to the present writer it seems unquestionable that Tertullian's work was the later. Of great moment also is the De Præscriptione Hæreticorum, in which the jurist is more clearly heard than the Christian. The De Spectaculis and De Idololatria show that Tertullian was already in a certain sense a Montanist before he formally went over to that creed ”

“ Among all the fathers of the first three centuries Tertullian has given the most powerful expression to the terrible earnestness of the Gospel.
(3) The course of Tertullian's personal development fitted him in an altogether remarkable degree to be a teacher of the church. Born at Carthage of good family—his father was a "centurio consularis"—he received a first-rate education both in Latin and in Greek. He was able to speak and write Greek, and gives evidence of familiarity alike with its prose and with its poetry ”

“ Tertullian both as a man and as a writer had much in common with the apostle Paul.
(2) In spite of all the contradictions in which he involved himself as a thinker and as a teacher, Tertullian was a compact ethical personality. What he was he was with his whole being. Once a Christian, he was determined to be so with all his soul, and to shake himself free of all half measures and compromises with the world. ”

“ His special gift lay in the power to make what had been traditionally received impressive, to give to it its proper form, and to gain for it new currency. From Rome Tertullian visited Greece and perhaps also Asia Minor; at any rate we know that he had temporary relations with the churches there. He was consequently placed in a position in which he could check the doctrine and practice of the Roman Church. Thus equipped with knowledge and experience, he returned to Carthage and there laid the foundation of Latin Christian literature. ”

“ He studied in Carthage, probably also in Rome, where, according to Eusebius, he enjoyed the reputation of being one of the most eminent jurists. This statement derives confirmation from the Digest, where references are made to two works, De Castrensi Peculio and Quæstionum Libri VIII., of a Roman jurist named Tertullian, who must have flourished about 180 A.D. In point of fact the quondam advocate never disappeared in the Christian presbyter. ”