This is Klaus Schilling's summary of "Het Oude Testament Als Christelijk Geschrift" by Gustaaf Adolf van den Bergh van Eysinga, http://www.radikalkritik.de/Het_oude_test.htm. Jan. 20, 2004. Formatted and copyedited by Michael Hoffman.
Critical scholars have to wonder why about 75% of the volume of the Christian Bible are taken by the scripture of the Jews.
The usual ritual for investing Catholic bishops involves an oath on acknowledging the law and the prophets as much as the apostles as guided and inspired by the same supreme being: "Credis etiam Novi et Veteris testamenti, legis et prophetarum et apostolorum unum esse auc-torem, Deum ac Dominum omnipotentem?" God is seen as having given both Old Testament and New Testament to the Catholic church. Similarly, Calvin insists on the authentic authorship of Old Testament and New Testament by the one God.
Some liberal protestants such as Windisch and Harnack advocate some sort of emancipation of the Christian church and the New Testament from the Old Testament.
van Eysinga shows that the emphasis on the identity of the source of the Old Testament and New Testament was a result of the struggle of dawning orthodoxy against the heresies that existed around their time. It is quite well-known that the heretic Marcion rejected the Old Testament from his canon. It's totally obvious that pessimistic Christians like Marcion can't accept the Lord of the Tanakh as their highest God, as the former is the Creator and thus is responsible for a disharmonic and horror-laden world.
And the rejection of the creator would imply the rejection of the Tanakh; at least many scholars seem to put it simply like this, though things are more complicated: the antithesis "Torah vs. Gospel" is, in Marcionite doctrine, only a secondary one. The antithesis between nature and God is more at the heart of the Marcionite doctrine. The demiurge, ignorant of true life, made man subject to the laws of nature. In reaching domination over nature, man had to break with the law of nature, and thus had to sin against the demiurge. Man in Law and nature are thus subject to deprecation and denial in Marcionite doctrine.
The Mosaic Torah is seen as an implementation of the law of nature. This gives us the rejection of the Torah by consequently world-pessimistic Christians.
For Marcion, the true God was utterly unknown until it revealed itself to Paul, his highest apostle. The prophesies of the Tanakh don't apply to the Christian saviour. Marcion does not need to deny the validity of the Tanakh; he can refer to the Messiah of the Tanakh -- for example, David, Cyrus, bar Kochba, or an as-yet unidentified eschatological figure -- as many literalist Jews did at some time.
Marcion's Christ comes to save us from the bondage of the natural world and make us children of the yet unknown God.
The question to be asked is whether the rough outline of the Marcionite doctrine applies to earliest Christianity as a whole, until Marcion had to break with the Roman power-mongers in early Antoninian time. If so, the Marcionite heresy would actually predate orthodox Christianity, which declared Marcion to be obsoleted.
Paul was the only (or single highest) apostle of concern to Marcion. Several theologians such as Karl Barth noted throughout church history that Paul was always at the margins of heresy. Marcion had a corpus of Paulinic writings related to the canonical epistles of Paul decades before the patrists accepted Paul as one of their apostles. It's completely plausible that Marcion's Paulinics don't depend on the canonicals, as the patrists love to claim (especially Tertullian in Against Marcion), but present a much more original state of the epistles.
Other heretical groups, such as Valentinus and Basilides, saw Paul as their highest apostle, and denied the value of the Lords [Lord?] of the Tanakh. According to most of the ancient heretics, the Law of the Tanakh couldn't have been given by the highest God, but rather, by a demiurge or deviant angels.
What was the particular value of the Old Testament that made it outstanding among ancient literature? On the one side, it starts with the beginning of the world, one the other side, it predicts the end times, and explains the present situation. The Greeks had nothing like that. The Jewish religion is the only one known in the ancient Roman empire that connects religion with an all-comprehensive history.
The Septuagint was already a first step towards a Hellenisation of the Hebrew religion. Christianity completed the step towards a universal religion. But already Philo praised the increasing universalisation of Judaism. The universalisation employed a certain degree of allegorisation as well.
Using older writings for purposes of bolstering one's authority is not restricted to Christianity; the Neoplatonists did so with the Orphic writings, but the patrists were by far the most successful in doing so.
The trick for the patrists was to divide the Old Testament into a part to be understood literally, and a part to be allegorised away. The literal part is for the common people day by day, the allegorical part is reserved for the scholars of theology. Jews protested against this illegitimate adoption of their scripture, and modern philosophers like Nietzsche were disgusted by the strategy.
Patrists tried to show that the Jewish people had lost its legitimacy to be considered as the chosen people of God, and that this is already predicted by the Tanakh, and that the Catholic church has superceded the covenant between God and the Hebrew people.
The selective exegesis of the Tanakh by Christian patrists is self-evident. In part, the law of the Torah is confirmed, in part it is obsoleted, reinterpreted, or blatantly ignored. The ceremonial law is, for example, held to be obsoleted by the Gospels. It was necessary at some point as preparation for the parousia, but is no longer in effect ever since that prophesied event came to pass.
The Catholic products called the 'Pastorals' emphasise the essential value of scripture as the word of God for refutation, proselytizing, and education. The monotheistic cosmology and worldview of the Tanakh was useful against the fanciful speculative mythology of the heretics. Many early Christian authors confessionally state that only the Tanakh guided them towards Christian belief. The first Letter of Clement stresses the anti-heretical value of the Tanakh.
While Basileides read in Romans 5:19 that the creation of the demiurge is hostile to the children of the true God, the Catholic Church holds that the Creation and revelation stem from the identical source. The Gnostic cosmophobia contrasts with the cosmophilia of the Catholic church.
The essential usage of the prophesies of the Tanakh by the Catholic church is that it is seen as predicting the parousia of Jesus throughout many previous centuries. According to the proto-Catholic Church, the Gospels would make no sense without the prophesies.
The Church emphasised the historical flesh-and-bone Jesus, against the docetism of the Gnostic heresies. This is also underscored by the Tanakh tales, which portrayed everything within a historical framework.
The patristic view did not emphasize the Tanakh history as the history of a people, but rather, of concepts that ultimately intended to point and lead to the Gospels. Jews objected of course to the Church doctrine that subdued their scripture as preparation for the Christian revelations by the Hagion Pneuma (Holy Spirit), making Jesus appear to be the central figure of the Tanakh.
Patrists such as Eirenaios object vehemently to the idea of separation of the roles of God and Creator, as maintained by many heretics.
The realism of the early Catholic community at Rome was typically Roman. Interestingly, 'reality' is a latinism, while otherwise grecisms like 'logics' prevail in metaphysics. The character of the Romans is stern and pragmatic. Law and order, not mythical fantasies characterise Roman religiosity. Myth is abandoned for history, as underlined by Cicero and Horacius.
Roman Christianity is characterised by its stern hierarchy and comprehensive organisation. The dualist cosmology of the heretics is seen as the worst blasphemy. Optimism is seen as obligatory for Catholics.
Christianity draws from Hellenic myths and rites, but the concept of theocracy is typically Jewish. And only the adoption of the Tanakh allowed for a successful theocracy. The Roman and Jewish mentality are closely related: they both mandate optimism and realism. Augustinus stressed the close vicinity of Judaism and the Roman Stoics. This convergence provided the launching pad for a Roman Christian church based on using the Tanakh as authority.
The Acta Apostolorum (Acts of the Apostles), a work of mid 2nd-Century proto-orthodoxy, plays a similar trumpet, connecting closely the ancient Jewish theocracy with the regime of the Church. Romans, like Jews, submitted to the pragma of Law-and-Order. Peter is seen as the new universal Moses, to which Paul is to be subdued. This was necessary for integrating mystics and common people within one unified Church.
Thus whatever appears to be Jewish in early Christianity is actually, properly Roman! In his Sixtinian chapel, Michelangelo Buonarrotti portrays Roman Sibyllines hand-in-hand with the prophets of the Tanakh. Helleno-Roman apocalypticists accepted the Jewish apocalyptics as related in mentality. In historical actuality, the Gospel travelled from Rome to Jerusalem, and not the other way round!