Musar su Isaia 60:19

Keeping this in mind you will understand that the loss of refined "Man" is the reason that until this day we cannot regain this hidden light as it was בתחלה, "in the beginning." This then is the meaning of the saying "על שלא ברכו בתורה תחלה." This explains Rashi's meaning when he referred to the words "אשר נתתי לפניהם" i.e. the previous, or original condition when G–d had made Torah available to man at the time of creation as a source of absolute enlightenment. There is yet a deeper meaning of the whole episode. We could have asked: If G–d knew He was going to have to conceal this light almost immediately, why did He bother to create and provide it in the first place? The answer to this is that the Celestial Spheres respond to stimulants originating in our spheres. G–d is only waiting until we provide the necessary stimulus by our conduct to once more place this light at our disposal. In order for this to happen this light first had to exist. Without such a stimulus forthcoming from the terrestrial regions the hidden light will remain forever hidden. It is this fact which the sages and prophets had been unaware of. They did not expound on this aspect though they were all perfectly aware of the existence of the hidden light, and many prophets had prophesied concerning its eventual restoration. Our sages have based the text of many prayers on the assumption that this light will be restored. They had not known that this development would depend on the benediction of the Torah.