"If I forget thee, O Jerusalem, let my right hand wither ..". This verse Teillim (137th Ps David King) are widely known and quote. Many people tend to think of it only literally, by the literal sense. However, the texts of the Tanach (Jewish and other books), as has been mentioned - there are complex codes. And Teillim are no exception here.

Jerusalem (Yerushalayim) - Perfect awe (Yira Slam). A "right hand" - MIDAT and Hesed, Mercy measure. In other words - the first achieved level (the highest) in awe of the Creator (and it has nothing to do before the banal fear), referred to as partial disclosure of the Face or Tshuva Mi-Yira (this is the stage at which a person is called secondary (Beynon) or non-full righteous). And since the spiritual is not "jumping through stages," that is impossible without making Awe final and complete correction of the stage at which "visible" (ie there) Right Arm - the mercy of the Creator of all created.

And if you "forget Jerusalem," ie, fall from stage partial opening - from "otstohnet Right Hand", i.e. disengage Full Disclosure and comprehension of Mercy ..