There are a few reasons.
The "Hebrew Scriptures" were written primarily in HEBREWand organized by Jews, members of the nation "entrusted with the very words of God.." (Romans 3:1, 2).
Also, 2 Corinthians 3:14, that in some translations refers to the term 'Old Testament', is actually referring to just the Mosaic Law, which prefigured the coming of Messiah. The Law alone became fulfilled and obsolete, when Christ died(Colossians 2:14), but the Hebrew scriptures as a whole remain an important part of the Bible, without which, much of the Greek Scriptures (New Testament) would be meaningless (2 Timothy 3:16;(Matthew 21:42; Romans 1:2; Luke 24:27, 44). Rather than implying that the Hebrew Scriptures were OLD , Jesus Christ and his disciples referred to them as "the Scriptures" and "the holy Scriptures." (Matthew 21:42; Romans 1:2)
For many Christians, the Bible is one work, in Hebrew, Greek and Aramaic, with nothing considered "old." It has one consistent message from Genesis to Revelation. (Romans 15:4; 2 Timothy 3:16, 17) Signifying sections of the Bible by language clarifies their location without diminishing their importance.
Roman Catholic AnswerThe Hebrew Bible, which Christians refer to as the "Old Testament" came from Judaism.
The Old Testament is primarily followed by Christians and Jews. Christians use both the Old and New Testaments as part of their religious scripture, while Jews primarily follow the Old Testament, which they refer to as the Tanakh.
Old Testament
All English copies of the Hebrew Scriptures are translated from Hebrew to English. These books are always called The Hebrew Bible (or the Tanakh, תנ״ך)Christians refer to these books as "The Old Testament"
The Hebrew Bible or Tanakh (×ª× ×´×š), which Christians refer to as "The Old Testament" is a set of laws intended for the Jewish religion. The first section of the Hebrew Bible is called the Torah (תורה), which contains all 613 laws.
But we do. Those who refer to the "Old Testament" either do so out of long habit, or because they simply do not realize that it is academically incorrect.
The Jewish bible is commonly referred to as the old testament or the Tanakh or the Hebrew Bible.*The most important texts are:the Torah (first five books of the Bible)the Bible, also called the Tanakh (known to Christians as the old testament)The MishnahThe TalmudAnd various historical writings from scholars and rabbis, such as the Shulchan Aruch, the Mishneh Torah, and the Zohar.*Only the Christians refer to the Hebrew Bible as "the Old Testament".
Christians adopted the Hebrew Bible, the holy book of the Jews, as the Old Testament of the Christian Bible because Jesus, Paul and the other authors of the Christian New Testament repeatedly quote from or refer to text in the Hebrew Bible. Had Christians abandoned that text, the references to it in the New Testament would make very little sense. After the death of Jesus, Christians read the Hebrew Bible very closely to re-interpret almost everything in Chritological terms. Jews generally find these reinterpretations amusing, at best and quite annoying at other times.
Catholics, and Christians in general, refer to the Hebrew Bible as the Old Testament. A more refined answer would note that Catholics accept the Apocrypha as canonical while Jews do not, so the Hebrew scriptures accepted by Catholics include the Jewish Hebrew Bible plus the Apocrypha.
There is none. The Hebrew Bible, or "Tanakh" (תנ״ך) only contains the books that Christians refer to as "the old testament." But the Old testament is not at all equivalent to the New testament. Both have entirely different information and messages.The New Testament was written in Greek only.There is an online version of the New Testament in Hebrew, but its quality is mediocre both in translation and in layout, and there are numbering mistakes throughout (verses are mislabeled in the Hebrew side, so the English verse doesn't alway match up to the correct Hebrew verse. you can view it here
The first Christians were Jews and were accustomed to Jewish scriptures which became Christian scripture as well.
The name of God, YHWH, is contained in the Hebrew translation of the TNK. When the TNK was translated into Greek, called the Septuagint, the name of God was still written in Hebrew. Later versions of the Septuagint use the phrase "THEOS KYRIOS (God is the Lord)," in place of the Hebrew for YHWH. When the Cristian new testament and the old testament (made up of Hebrew scriptures) where translated into Latin (called the Vulgate) the name of God was translated as IEHOVAH (the LORD). Modern Christians refer to God as Jehovah, because the modern bibles were translated directly from the Vulgate.