In Parshas Breishis ( Genesis) we’re told that G-d created leather garments for Man and his Wife, (3:21). Arizal explains that the original Adam and Chava (Eve) were clothed in the light emanating from the world of CHASHMAL. In Adam and Eve’s original refined state there was no place for concealment. Because of the transgression of the Tree of Knowledge, they now had the ability to conceal which led to their ability to dress in what the Kabbala calls «snake skin».
Such «clothing», of course, has some limitations - but this is where its main advantage lies. Indeed, this feature (the ability to hide) is not possessed by any of the inhabitants of the spiritual worlds put together. However, it is desirable to take advantage of this property for the benefit.
The numerical difference between the words Light (אור) and Skin (עור), (which are pronounced identically in Hebrew) is 69. One of the two major names of the Serpent is Yagon (יגון). This name is mentioned every day in prayer (הסר ממנו יגון ואנחה) with a request to save us from the pressures of the Serpent and help us realize our unique abilities. The gematria of the word «Yagon» is 69!