Regarding these 13 principles I prefaced some remarks on the parent page here
The Rambam writes in his third principle that G-d does not have a body nor any physicality whatsoever. That this previously mentioned Entity which is One, is not a body nor the power of a body. Moreover, those things which happen to a body, for example movement or rest, do not occur to G-d, neither intrinsically nor by chance. Our sages tell us (according to the Rambam’s explanation of the Talmud Chagiga), that G-d has no sitting nor standing, no connecting nor disconnecting.
The prophet says (Isaiah) “To whom am I comparable that you should consider me alike, says the Holy One”, and if He had a body, He would be comparable to others from the standpoint of the body.
The Rambam explains that this that we find that the Bible describes G-d with various descriptions like going, standing, sitting, speaking, and so on, these are all borrowed phrases that don’t actually literally apply. Our sages said in the Talmud (Brochos), that the Torah expresses itself in the language of people, and the sages spoke about this point at length in many places.
The Rambam says that this third principle is contained in that what the Almight’y exhorts the Jewish people regarding the receiving of the Torah at Mt. Sinai, “(Note that) you did not see any image…” meaning, that the prophecy that the whole Jewish people experienced there at Mt. Sinai, the revelation of G-d Himself, they did not see nor otherwise experience anything corporeal, because like the Rambam wrote above, G-d is not a body nor the power of a body.
