What then was the basis of [Jewish] belief? The
Revelation at Mount Sinai, which we saw with our own eyes and
heard with our own ears, not dependent on the testimony of others...
as it says, "Face to face, God spoke with you..." The
Torah also states: "God did not make this covenant with our
fathers, but with us -- who are all here alive today." (Deut.
5:3)
Judaism is not miracles. It is the personal eyewitness
experience of every man, woman and child, standing at Mount Sinai
3,300 years ago.
Christianity contradicts Jewish theology
The
following theological points apply primarily to the Roman Catholic
Church, the largest Christian denomination
A. GOD AS THREE 
The Catholic
idea
of Trinity breaks God into three separate beings: The Father,
the Son and the Holy Ghost (Matthew 28:19). Contrast this to the
Shema, the basis of Jewish belief: "Hear O Israel, the Lord
our God, the Lord is ONE" (Deut. 6:4). Jews declare the Shema
every day, while writing it on doorposts (Mezuzah), and binding
it to the hand and head (Tefillin). This statement of God's Oneness
is the first words a Jewish child is taught to say, and the last
words uttered before a Jew dies.
In Jewish law, worship of a three-part god is considered
idolatry -- one of the three cardinal sins that a Jew should rather
give up his life than transgress. This explains why during the
Inquisitions and throughout history, Jews gave up their lives
rather than convert.
B. MAN AS GOD?
Roman Catholics believe
that
God came down to earth in human form, as Jesus said: "I and
the Father are one" (John 10:30). Maimonides devotes most
of the "Guide for the Perplexed" to the fundamental
idea that God is incorporeal, meaning that He assumes no physical
form. God is Eternal, above time. He is Infinite, beyond space.
He cannot be born, and cannot die. Saying that God assumes human
form makes God small, diminishing both His unity and His divinity.
As the Torah says: "God is not a mortal" (Numbers 23:19).
Judaism says that the Messiah will be born of human
parents, and possess normal physical attributes like other people.
He will not be a demigod, and will not possess supernatural qualities.
In fact, an individual is alive in every generation with the capacity
to step into the role of the Messiah. (see Maimonides - Laws of
Kings 11:3)
C. INTERMEDIARY FOR PRAYER?
The Catholic belief is
that prayer must be directed through an intermediary -- i.e. confessing
one's sins to a priest. Jesus himself is an intermediary, as Jesus
said: "No man cometh unto the Father but by me."
In Judaism, prayer is a totally private matter, between each individual
and God. As the Bible says: "God is near to all who call
unto Him" (Psalms 145:18). Further, the Ten Commandments
state: "You shall have no other gods BEFORE ME," meaning
that it is forbidden to set up a mediator between God and man.
(See Maimonides - Laws of Idolatry ch. 1)
D. INVOLVEMENT IN THE PHYSICAL
WORLD
Catholic doctrine often treats
the
physical world as an evil to be avoided. Mary, the holiest woman,
is portrayed as a virgin. Priests and nuns are celibate. And monasteries
are in remote, secluded locations.
By contrast, Judaism believes that God created the physical world
not to frustrate us, but for our pleasure. Jewish spirituality
comes through grappling with the mundane world in a way that uplifts
and elevates. Sex in the proper context is one of the holiest
acts we can perform.
The Talmud says if a person has the opportunity
to taste a new fruit and refuses to do so, he will have to account
for that in the World to Come. Jewish rabbinical schools teach
how to live amidst the bustle of commercial activity. Jews don't
retreat from life, we elevate it.
Jews and Gentiles
Judaism does not demand that everyone convert to
the religion. The Torah of Moses is a truth for all humanity,
whether Jewish or not. King Solomon asked God to heed the prayers
of non-Jews who come to the Holy Temple (Kings I 8:41-43). The
prophet Isaiah refers to the Temple as a "House for all nations."
The Temple service during Sukkot featured 70 bull offerings, corresponding
to the 70 nations of the world. The Talmud says that if the Romans
would have realized how much benefit they were getting from the
Temple, they'd never have destroyed it.
Jews have never actively sought converts to Judaism
because the Torah prescribes a righteous path for gentiles to
follow, known as the "Seven Laws of Noah." Maimonides
explains that any human being who faithfully observes these basic
moral laws earns a proper place in heaven.
Bringing the Messiah
Maimonides states that the popularity of Christianity
(and Islam) is part of God's plan to spread the ideals of Torah
throughout the world. This moves society closer to a perfected
state of morality and toward a greater understanding of God. All
this is in preparation for the Messianic age.
Indeed, the world is in desperate need of Messianic
redemption. War and pollution threaten our planet; ego and confusion
erode family life. To the extent we are aware of the problems
of society, is the extent we will yearn for redemption. As the
Talmud says, one of the first questions a Jew is asked on Judgment
Day is: "Did you yearn for the arrival of the Messiah?"
How can we hasten the coming of the Messiah? The
best way is to love all humanity generously, to keep the mitzvot
of the Torah (as best we can), and to encourage others to do so
as well. Despite the gloom, the world does seem headed toward
redemption. One apparent sign is that the Jewish people have returned
to the Land of Israel and made it bloom again. Additionally, a
major movement is afoot of young Jews returning to Torah tradition.