Christian Practice.—Though Tatian does not speak of his co-religionists as Christians, but accepts willingly the contemptuous expression "barbarians," it is the doctrines of Christ which alone have, in his opinion, raised them above a world deluded by the trickeries of frenzied demons (c. xii.), and wallowing in matter and mud (c. xxi.). Where the old nature has been laid aside, men have not only apprehended God (c. xi.), but through a knowledge of the True One have remodelled (μεταῤῥυθμίζειν) their lives (c. v.). Holy baptism and membership in the church did not enter into his argument. A passing allusion to the Holy Eucharist perhaps underlies his indignant protest against the frequent defamation that Christians indulged in Thyestean banquets (c. xxv.). He seems to prefer advancing the great help which the Scriptures had been to himself, and might be to his philosophical opponents. "Barbaric" though these Scriptures were, they were in the O.T. portion both older and more divine, more full of humility and of deep knowledge, more marked by excellence and unity than any writings claimed by the Greeks (c. xxix.). These "divine writings" made men "lovers of God" (c. xii.); and men thus God-taught were helped by them to break down the slavery in the world, and gain back what they had once received, but had lost through the deceit of their spiritual foes (c. xxix.).
The O.T. seems to have greatly attracted Tatian. It probably formed the basis of the lost work προβλημάτων βιβλίον mentioned by Rhodon; and in his attempt to collect and solve O.T. difficulties, Tatian was among the first, if not the first, of Christian commentators. The Oratio shews that he knew well the Gospels, Acts, and Pauline Epistles. If reference to O. and N. T. is more marked by allusion than by direct quotation, the cause is the well-known practice of the apologists, who usually abstain from such quotations when writing to Gentiles who would have allowed little authority to them. Tatian's references to St. John's Gospel are, however, both exceptional and indisputable, and testify to a widespread knowledge of that Gospel at the period in question. Independently of coincidences of exposition, three passages may be specified:
| TATIAN. | ST. JOHN. | ||
| Ch. iv. | πνεῦμα ὁ Θεός | Ch. iv. 24. | πνεῦμα ὁ Θεός. |
| Ch. xiii. | ἡ σκοτία τὸ φῶς οὐ καταλαμβάνει. | Ch. i. 5. | τὸ φῶς ἐν τῇ σκοτίᾳ φαίνει, καὶ ἡ σκοτία αὐτὸ οὐ κατέλαβεν. |
| Ch. xix. | πάντα ὑπ᾿ αὐτοῦ καὶ χωρὶς αὐτοῦ γέγονεν οὐδε ἕν. | Ch. i. 3. | πάντα δι᾿ α αὐτοῦ ἐγένετο, καὶ χωρὶς αὐτοῦ ἐγένετο οὐδὲ ἕν. (Westcott & Hort.) |
Of these the second is prefaced by τὸ εἰρημένον, the expression which in N.T. introduces the Scriptures (cf. Luke ii. 24; Acts ii. 16, xiii. 40; Rom. iv. 18). The third passage is punctuated by Tatian in the manner invariably followed by the early Christian writers (contrast the textus receptus, οὐδὲ ἓν ὃ γέγονεν). The coincidence is, as noted by Bp. Lightfoot, remarkable, for the words are extremely simple in themselves. Their order and adaptation give uniqueness to the expression.
B. The Diatessaron.—(1) History.—The history of the recovery of this work is sufficiently romantic. In the literature of the Western church there is no serviceable testimony to it till the middle of 6th cent.; in the Eastern church Eusebius († 339–340) is the only Greek writer of the first four cents. who gives any information about it. It was apparently (see Codex Fuldensis, ed. Ranke, 1868, ix. 1) mere chance which put into the hands of bp. Victor of Capua († 554) a Latin book of the Gospels without title or author's name, but evidently compiled from the four canonical books. This unknown work excited his interest; and searching in vain the Latin Christian literature of the past, he turned to the Greek, and found in Eusebius two notices of Harmonies. (a) In the letter to Carpianus the harmony of Ammonius of Alexandria (3rd cent.) was described. Its principle was that of comparison. The Gospel of St. Matthew was followed continuously, and the passages—and only those—from the other Gospels which tallied with the text of St. Matthew were referred to or inserted in the margin or in parallel columns. This excluded the greater part of St. John's Gospel and much of St. Luke's. The Harmony was for private use, not for the public service of the church. Whether or not the descriptive title given to it in Eusebius—τὸ διὰ τεσσάρων εὐαγγέλιον—was that of the church historian or of Ammonius remains undetermined. (b) In his Church History (iv. 29, 6), Eusebius refers to Tatian as having composed a "sort of connexion or compilation, I know not how, of the Gospels, and called it the Diatessaron" (συνάφειαν τινα καὶ συναγωγὴν οὐκ οἶδ᾿ ὅπως τῶν εὐαγγελίων συνθείς.) Cf. Bp. Lightfoot in Contemp Rev. May 1877; Zahn, i. pp. 14, 15); and he adds that this work was current in his day. Its principle was amalgamation, not comparison. Victor came to the conclusion that his unknown work was substantially the Diatessaron of Tatian. This acute verdict—purged of some unimportant errors (see Lightfoot, l.c.; Zahn, i. pp. 2, 3)—has survived the difficulties which a comparison of the Codex Fuldensis with the Diatessaron at first presented.
A notice in the treatise on Heresies, written in 453 by Theodoret († 457–458), bp. of Cyrrhus on the Euphrates, is the first definite evidence to the Diatessaron after the time of Eusebius. The identification of it by Epiphanius (Haer. xlvi. 1) with the Gospel according to the Hebrews is an earlier testimony in point of date (Epiphanius † 403), but is connected with a blunder which, though capable of explanation, somewhat disqualifies the evidence. Testimony to the Diatessaron comes rather from the Syriac-speaking church of the East than from the Greek. Theodoret says of Tatian: "He composed the Gospel which is called Diatessaron, cutting out the genealogies and such other passages as shew the Lord to have been born of the seed of David after the flesh. This work was in use not only among persons belonging to his sect, but also among those who follow the apostolic doctrine, as they did not perceive the mischief of the
