"I believe with perfect faith that G-d does not have a body and that physical concepts do not apply to Him. There is nothing whatsoever that resembles Him at all."
The third fundamental principle of Judaism is that G-d is non-corporeal. G-d has no form or image. G-d is completely beyond time and space, unfettered by the dimensions which He has created. Since G-d is by definition limitless, He cannot have a physical body which is by nature limited. It is similar to the conundrum if G-d could create a rock which He could not lift. The traditional answer is that such a rock could not be created since G-d cannot be restricted. A paradox? Certainly. Just as paradoxical as saying that G-d cannot have a corporeal form as this would be a limit on Him.
Besides philosophical ruminations, the Torah states emphatically that at Mount Sinai, the Jewish people saw no form. The entire nation, men, women and children, millions who left Egypt, all had G-d manifest Himself to them at Sinai. As the Sages said, a maidservant at the Sea (and by extension at Sinai) saw more of G-d than Ezekiel saw in his heavenly vision. And yet, at this ultimate moment, G-d had no form or image. "And the LORD spoke unto you out of the midst of the fire; ye heard the voice of words, but ye saw no form; only a voice... Take ye therefore good heed unto yourselves--for ye saw no manner of form on the day that the LORD spoke unto you in Horeb out of the midst of the fire-- lest ye deal corruptly, and make you a graven image, even the form of any figure, the likeness of male or female." (Deut. 4:12,15-16) The fear that the nation of Israel would mistakenly assume that since G-d interacted with His world, that He would have a physical body, was ever-present. To prevent this, the Torah warned the Jewish nation sternly that we should not deal corruptly and believe that G-d has a form.
Christianity holds that Jesus was both fully human and fully divine at the same time. In other words, they hold that G-d was incarnated in the flesh as a man (chas v'shalom). Of course, logic and plain reading skills have never been Christianity's strong spot. As the Torah says, G-d was not a man. "God is not a man, that He should lie; neither the son of man, that He should repent." (Num. 23:19) In case anybody missed that verse, the Torah repeats it. "And also the Glory of Israel will not lie nor repent; for He is not a man, that He should repent.'" (I Sam. 15:29) Of course, this shoots Christianity's claims down so expect missionaries to squirm and wiggle this verse into something that it isn't. Did you miss that? Well here it is again. "I will not execute the fierceness of Mine anger, I will not return to destroy Ephraim; for I am God, and not man, the Holy One in the midst of thee; and I will not come in fury." (Hosea 11:9) Hmm... that must mean that G-d is really a first century Jewish preacher. No quite. In Psalm 146:3, we are directed not to put our hope in the "son of man." Interestingly, Jesus is called the "son of man" throughout the Christian Bible. For instance, Jesus calls himself the "son of man" at the Last Supper in Matthew 26:24. He calls himself the "son of man" in many other places, such as in Luke 6:5, when he also declares himself to be a god. Clearly, this does not match G-d's statements in the Jewish Bible that G-d is not a human.
Christians love to point to Genesis 18 as proof that G-d made Himself manifest in the flesh. This obviously misses the point of the story. Leave it to Christians to insert Jesus where he doesn't belong. Of course, a Jew who was raise in Jewish tradition would understand the Torah properly. But certainly goyyim know the Torah better than us. But I digress...
א וַיֵּרָא אֵלָיו יְהוָה, בְּאֵלֹנֵי מַמְרֵא; וְהוּא יֹשֵׁב פֶּתַח-הָאֹהֶל, כְּחֹם הַיּוֹם.
1 And the LORD appeared unto him by the terebinths of Mamre, as he sat in the tent door in the heat of the day;
What was G-d doing appearing to Abraham? Abraham had circumcised himself 3 days prior at age 99, an obviously painful experience. Here we learn the important of visiting the sick. In the next verse, we see that Abraham saw three men appearing on the horizon. Note that G-d was there prior to the appearance of them. Therefore, G-d could not have been one of the men.
ב וַיִּשָּׂא עֵינָיו, וַיַּרְא, וְהִנֵּה שְׁלֹשָׁה אֲנָשִׁים, נִצָּבִים עָלָיו; וַיַּרְא, וַיָּרָץ לִקְרָאתָם מִפֶּתַח הָאֹהֶל, וַיִּשְׁתַּחוּ, אָרְצָה.
2 and he lifted up his eyes and looked, and, lo, three men stood over against him; and when he saw them, he ran to meet them from the tent door, and bowed down to the earth
Our Sages learn from here that it is more important to greet guests and to provide them with good hospitality than to be in the presence of G-d. Abraham, the epitome of Jewish hospitality, ran to greet the three men, angels in disguise that G-d had sent to him. Keep in mind that G-d was already there visiting the sick Abraham before the men appeared. If a person still believes that G-d was one of the men, then the valuable lesson was completely lost.
ג וַיֹּאמַר: אֲדֹנָי, אִם-נָא מָצָאתִי חֵן בְּעֵינֶיךָ--אַל-נָא תַעֲבֹר, מֵעַל עַבְדֶּךָ.
3 and said: 'My lord, if now I have found favour in thy sight, pass not away, I pray thee, from thy servant.
Messianics/ Christians love to point out the use of the word "my lord". Too bad that their Hebrew sucks. When G-d is refered to in the Torah by the word "my lord", it is written as the Tetragramatton, G-d's 4 letter name, and pronounced as ADONAI. Here, the word ADONAI is spelled out, making it clear that is referring to somebody other than G-d. Here, Abraham is politely addressing the angels as his lords. It is wrong to assume that Abraham was addressing the men as G-d as we have already stated that G-d was there prior to their arrival. There is further evidence that the word "lords/ ADONAI" can be used to refer to creatures other than G-d. In Genesis 19:1 we read that Lot is visited by two of these three angels, and in verse 19:2 he addresses the angels, saying: "Behold now, my lords..."
The controversy is cleared up when we reach verse 22.
כב וַיִּפְנוּ מִשָּׁם הָאֲנָשִׁים, וַיֵּלְכוּ סְדֹמָה; וְאַבְרָהָם--עוֹדֶנּוּ עֹמֵד, לִפְנֵי יְהוָה.
22 And the men turned from thence, and went toward Sodom; but Abraham stood yet before the LORD.
Even when the men had left, Abraham was still standing before G-d, whom he had temporaily left to serve his guests.
Missionaries point out that three men came to Abraham and only two visited Lot. In the demented thinking of Christianity, this means that one man had to be G-d. This again misses the point. G-d created many spiritual beings, angels, each with a purpose. No angel is ever assigned to more than one task. In Genesis 18, we had three angels, but they did not have the same job. The first angel's job was to inform Abraham of Sarah's impending pregnancy, while the other two angels' jobs had to do with Lot, Sodom and Gemorrah. After the first angel had informed Abraham of the pregnancy, the angel was done with the job. Hence, only two angels visited with Lot. So, we see that the third man/angel was not G-d, but an angel, who did not go to visit Lot in Genesis 19 because that was not G-d's purpose for the angel.