דבר שלא בא לעולם הדרן

Maimonides, Guide, Chapter 16, Section I

Standing. Even though these two roots are different, the meaning, as you know, is one regardless of how it is spelled. This word has multiple meanings. Sometimes it means standing straight. . . . Sometimes it means fixedness and persistence. . . Whenever it is said regarding the Creator, it is the second meaning. "And behold God was standing upon it" - fixed, persistent upon it. In other words, on the ladder, whose one end is in Heaven and the other end on Earth, and upon which climb and rise all those who rise, until they necessarily perceive he that is upon it, since he is fixed and persistent at the top of the ladder, and it should be clear that when I say "upon" it is by way of this parable. "And the angels of God" they are the prophets . . .

How perfect are his words, "Go up and go down." The going up precedes the going down, because after you go up and reach a certain known place on the ladder, the going down must come, together with the order that he received to lead the people of Earth and to teach them. This is what is described as going down, as we explained. . . .