Why does the Christian Church consider the Old Testament to be an integral part of the Holy Bible?

The Church ties readings from the Old Testament to those from the New Testament in all its liturgical prayers. The Church also firmly resisted the various heretics⁶⁸¹ who attempted to exclude the books of the Old Testament from canon of the Holy Bible.

St. Paul writes, “Christ is the end of the law for righteousness for everyone who believes, for Moses writes this about the righteousness which is of the law: ‘The man that does those things shall live by them.’” (Rom. 10:4–5). The apostle Paul is quoting Moses here: “You shall therefore keep my statutes and my judgments which if a man does he shall live by them” (Lev.18:5). St. John Chrysostom⁶⁸² tells us that man can neither live nor be righteous unless he fulfills all the statutes of the law—a feat that we must admit is beyond human ability. If the Jews base their righteousness on adherence to the law, the law itself declares the utter inability of humans to achieve righteousness and life. This leads us to faith in our Lord Jesus Christ who alone among humanity has not broken the law, but is able to make those who believe in Him righteous. This why the apostle Paul does not allow the Jews any excuse, for the law itself declares Christ as the only One who is righteous in the sense of righteousness intended by the law. To reject Him is to reject righteousness, even if one thinks that he is made righteous by the law. St. Clement of Alexandria says, “‘For Christ is the end of the law for righteousness’ (Rom. 10:4), who was prophesied by the law to every one who believes.”⁶⁸³

The Jews are proud of the fact that they are the people of God who received the divine law by Moses through angels (Heb. 2:2). But now the incarnate Word Himself has come to us, giving Himself to us, and granted us to be the children of the Father in the waters of baptism through the Holy Spirit. St. Augustine says, “He who gave the law likewise gave grace; but the law He sent by a servant, with grace He Himself came down.”⁶⁸⁴

680 See St. Didymus Study Group: Salvation Service, 2007, Topic VI, Law and Prophecies .

681 Among the most famous of these is Marcion from the second century, whose rejection of the books of the Old Testament was connected to his denial of the divinity of the Lord Christ.

682 St. John Chrysostom, Homilies on Romans 17 (NPNF I/11:471–477).

683 St. Clement of Alexandria, The Stromata, or Miscellanies 2.9 (ANF 2:357) amended.

684

St. Augustine of Hippo, Lectures or Tractates on the Gospel According to St. John 3.2 (NPNF I/7:19) amended.