This week's Torah portion includes the verses of the Shema, the most important prayer in all of Judaism.
In it we declare that "...Hashem is our G-d, Hashem is One."
The simple meaning of this declaration is that there is only one G-d. But the deeper meaning is that G-d is the one and only true existence, and that there can be no existence 'outside' of G-d.
The Hebrew word for One, "Echad," consists of three letters: Alef, Chet, Dalet. Alef has the numerical value of 1, representing the Creator, Chet has the numerical value of 8, representing the 1 earth and 7 heavens, and Dalet has the numerical value of 4, representing the 4 directions (north, south, east and west). So the word Echad itself contains a hint to this fundamental concept: that there is One Creator (Alef) who is the only sovereign on earth and in the heavens (Chet), and in all four directions (Dalet).