The *nature* of the OT writings is, of course, another question, but Christ Himself is the key to many of the questions we ask about the canonicity of the proto-canon and some of the deuterocanon of the Old Testament long before the early fathers presumed upon the question; the latter did not diverge at all from the teachings of Christ as reported in the New Testament documents as e.g. Marcion the heretic and others did (not before mid second century).
Frequently we find on the lips of Jesus the phrase “it stands written”; it is multiply attested and occurs in parallel passages of the earliest New Testament sources; it indicates that appeal to scripture formed a central characteristic of his ministry. Jesus’ view of what for him constituted Old Testament scripture presupposes the New Testament attestation to Jesus’ view of the OT is reliable; it is not necessary to assume the New Testament as scripture to establish Jesus’ view of the Old Testament.
Jesus’ high view of scripture is evidenced throughout the Gospels, e.g.:Matthew 5:17-19: "Do not think that I came to abolish the Law or the Prophets; I did not come to abolish, but to fulfill. For truly I say to you, until heaven and earth pass away, not the smallest letter or stroke shall pass away from the Law, until all is accomplished. Whoever then annuls one of the least of these commandments, and so teaches others, shall be called least in the kingdom of heaven; but whoever keeps and teaches them, he shall be called great in the kingdom of heaven.”; Matthew 22:29: “But Jesus answered and said to them, ‘You are mistaken, not understanding the Scriptures, or the power of God’”; Jn 10:35: “the scripture cannot be broken”; Luke 24:44-45: all things which are written about Me in the Law of Moses and the Prophets and the Psalms must be fulfilled. Then He opened their minds to understand the Scriptures” is a post-resurrection pericope which clearly reflects the central message of the earliest Christian kerygma, which can be firmly established within a very short period after the resurrection on firm historical-critical grounds. These are just selected examples.
Shorthand for the OT in early Judaism and Christianity: Law and the Prophets; Law, Writings and Prophets; Law, Writings, Prophets and Psalms.
“The Law and the Prophets”: The earliest division of the OT was a twofold division known as the Law and the Prophets. This terminology goes back to the OT itself: “Law of Moses” (Dan 9:11, 13); “prophets” (Dan 9:6); The Law of Moses as “Thy Law” (Neh 9:29); God also “admonished them by Thy Spirit through Thy prophets” (Neh 9:30); “the law and …the former prophets” (Zech 7:12); “the law and the prophets” (2 Macc 15:9); “law and the prophets” (Manual of Discipline I.3; VIII.15; IX.11).
A twofold division of the Law and the Prophets was spoken of by Jesus (e.g. Matt 5:17; 7:12; 22:40; Lk 16:16, 29, 31; 24:27; Acts 13:15; 26:22). A two-fold division is multiply attested in ancient Judaism. The “Law and the Prophets” (Mt 5:17; Lk 16:16), referred to as “all the scriptures” (Lk 24:27) were said to contain “everything written” about Christ (Lk 24:44). “All the Scriptures” (e.g. Lk 24:27: “And beginning with Moses and with all the prophets, He explained to them the things concerning Himself in all the Scriptures”). Josephus lists 24 books of the OT (Against Apion I.
and refers there the two-fold division of the Law and the Prophets. Paul said he believed “everything laid down by the law or written in the prophets” (Acts 24:14; cf. 26:22). Portions of the OT later classified as “Writings” by the Talmud (Job, Psalms, Proverbs, Daniel) were earlier included within the two-fold division “Law and Prophets” (cf. Matt 24:15; Lk 4:8-11; Jn 10:34; 1 Cor 3:19). There are also NT references to parts of the Deuterocanon (which topic I will leave aside for another thread); the entirety of the DC not yet having been completed.
Other Divisions of the OT canon: threefold and fourfold schematic divisions are attested after the twofold division scheme; the contents of the OT canon are unaffected by this division. Threefold Division: “prophets” divided into “the prophets and the writings” giving the threefold Law (Torah), Prophets (Nebhiim), and Writings (Kethubhim). The Fourfold scheme is reflected in the LXX: Law, History, Poetry, and Prophecy; Jerome’s Vulgate and English translations of the Bible follow this arrangement. Philo spoke of “the laws and oracles delivered through the mouth of the prophets, and psalms, and anything else which fosters perfect knowledge and piety” (De Vita Contemplativa III.25). Luke presents Jesus as saying “everything written about me in the law of Moses and the prophets and the psalms must be fulfilled” (Lk 24:44).
An attempt to present the historical Jesus, who all contemporary scholars regard as *Jewish* -as at radically at odds with the Old Testament, is not really credible on even radical premises of historical critical reconstruction given the nature and mulitiplicity of attestation. Any attempt to suppose Paul held such a view is completley out of the question. Any notion of Orthodox Christianity without an Old Testament canon is also completely out of the question; the same is true of Roman Catholicism and Protestantism. At best we are on the extreme fringe -with reasonable warrant well beyond what we might reasonably call Christendom and haunted by some of the more infamous heretics of old on such a hypothesis of excising the Old Testament from the Christian faith.