Prophecy and Graven Images
Moshe Rabbeinu felt it necessary to clarify an important aspect of prophecy as it relates to our perception of Hashem. He does not want there to be any confusion with as it relates to G-d not having any physical form.
Moshe focused on the Revelation at Mount Sinai. He reminds the people that they did not see a physical form of G-d while in a conscious state. This implies that it is possible to have such a perception in a non-conscious state. This takes place when one is transformed to a state of prophecy. This actually occurred at Mount Sinai and it occurred seven weeks before during the splitting of the Red Sea.
In both instances, the nation was elevated to a prophetic state. At Mount Sinai, they saw G-d as a saintly sage with a long white beard. And at the Red Sea, they saw Him as a brave warrior.
It is important to understand this distinction, so that one not be dragged into confusion about G-d. The basic principle that G-d has no physical form is etched in stone. Such a belief would minimize the infinite nature of Hashem. He has no limits and cannot be confined to a body.
Prophecy lasted for 1000 years and no longer exists today. It is difficult for us to even comprehend what prophecy really was. We believe it will return in Messianic times. In the meantime, it is our duty to connect with the living G-d who has no physical form. This is enough of a task that should be the main priority of our lives.