At the giving of the Torah, God's speech was heard coming from any direction one faced—not only from Mt. Sinai, not only from a single concealed focal point, but from all directions: the four points of the compass, above and below, within and without.
This revelation burst forth—direct and unmediated—through the boundaries of space to go beyond what is normally understood, beyond the grasp of the senses—even beyond the dimensions of time and space.
This was a revelation of the type that will occur in future days, when "your Teacher will no longer hide," when the garments of our lowly physical world will be removed.
This is a revelation that in essence has no physical form but that we interpret as possessing physical characteristics—as being visible, audible, and so forth.
And so the words arrived from any direction that one listened and received any physical garb that one stood ready to receive.
–Rabbi Adin Steinsaltz
From Understanding the Tanya, p. 228, by Rabbi Adin Steinsaltz