I reread your post today and I think I now know what you're trying to say. Essentially it appears that you're saying Christians are picking and choosing which parts of the bible they what to believe in (e.g. why aren't Christians stoning people for their transgressions under Mosiac Law known as the "Old Covenant"?)
Here's a link that explains this the difference in covenants. Please let me know if you have any questions.
http://en.wikipedia.org/wiki/Christian_views_on_the_old_covenant
Christian views on the old covenant
Christian views of the
Old Covenant are central to
Christian theology,
ethics, and
practice. The term "Old Covenant", also referred to as the
Mosaic Covenant,
Mosaic Law,
Divine Law, Biblical Law, God's Law, or the
Books of Moses, refers to the statements or principles of
religious law and
religious ethics codified in the "first five books" or
Pentateuch of the
Old Testament. Views of the Old Covenant are expressed in the
New Testament, such as
Jesus'
antitheses of the law, the
circumcision controversy in Early Christianity, and the
Incident at Antioch and position of
Paul the Apostle and Judaism. Many traditional Christians have the view that
only parts are applicable, many
Protestants have the view that
none is applicable,
dual-covenant theologians have the view that only
Noahide Laws apply to
Gentiles, and a minority have the view that
all are still applicable to believers in
Jesus and the
New Covenant.
In
Judaism, the "first five books" are referred to as the
Torah, in
Hebrew:
תּוֹרָה‎,
[2] and generally translated as "the Law" in
English translations of the Bible.
Rabbinic Judaism[3] asserts that the
Laws of the Jewish Bible were presented to the
Jewish people and
converts to Judaism (which includes the
biblical proselytes) and do not apply to
Gentiles, including Christians, with the notable exception of the
Seven Laws of Noah which apply to all people.
Rabbi Emden of the 18th century was of the opinion that Jesus' original objective, and especially Paul's, was only to convert Gentiles to Noahide Law while allowing Jews to follow full Mosaic Law.
Although Christianity affirms that the
Pentateuch is part of Scripture that is
inspired of God, Christian tradition, in this case similar to Jewish tradition, denies that all of the Old Covenant still applies directly to Christians, but different arguments are used to reach that conclusion and there are differences of opinion within Christianity as to which parts, if any, still apply.
The predominant Christian view is that Jesus mediates a New Covenant relationship between God and his followers, according to the New Testament, which ended or set aside some or all of the Old Covenant.[4] Christianity, almost without exception, teaches that this New Covenant is the instrument through which God offers mercy and atonement to mankind. However, there are differences of opinion as to how the
New Covenant affects the validity of the
Old Covenant, how many
Old Covenant laws such as the
Ten Commandments are continued or renewed in the
New Covenant, and related issues. The differences are mainly as a result of
attempts to harmonize biblical statements to the effect that the Old Covenant and its law is "perpetual"
[5] or "everlasting"
[6] or "lasting"
[7] with biblical statements to the effect that it does not apply anymore (in the current
dispensation) or at least does not fully apply.
[8] The topic of
Paul and the Old Covenant is still frequently debated among New Testament scholars leading to many views.