“And there was thunder and lightning” (Exodus 19:16). Now, at first glance, was it really necessary for the Holy One Blessed Be He to threaten the Jewish people? Rather, the matter is as follows; that at the time of the giving of the Torah the Holy One Blessed Be He showed man how to conduct himself in his service of G-d.
For in the current state of things, the world operates in a manner in which G-dliness is concealed, as stated (Deut. 31:18), “I shall surely conceal my face.” That is to say, G-d conceals himself from man, as explained in the analogy of a father who conceals himself from a child to see if he will seek him out (Intr. to Shaar HaEmunah). It is the task of man to seek Him and grasp Him through Torah and good deeds.
Now, when a person becomes coarsened through physical eating and drinking and then subsequently desires to cleave to the Holy One Blessed Be He, it is impossible to do this with haste, for these two matters are diametric opposites. Therefore, he must do this by first arousing his intellectual intention, whereby there will come to be an arousal of love and excitement towards G-d in his heart. However, after the excitement withdraws he will return to darkness, which is the state he was in at first.
With the above verse at the giving of the Torah, the Holy One Blessed Be He is teaching us that one should not become saddened by this return to darkness. For as it states (Ezekiel 1:14), “the Chayot ran and returned, like the appearance of lightning,” i.e., just like after thunder there is lightning and light, but it is immediately followed by darkness and becomes dark, so likewise with the service of G-d.
That is to say, the verse may be interpreted as follows; “And there was Kolot (thunder)” means that a person first arouses his intellectual intention toward G-d with his Kol-his voice in the study (which increases concentration and intention). Through this he will have the “Barak-lightenting” flash of intuition and insight, and the light of his emotions. And although this is immediately followed by the Arafel-darkness when it recedes, he should not worry, for this is the aspect of the darkness of G-d concealing himself so that he should continue to seek Him out.
For the G-dliness in the darkness could only be revealed to Moshe, since ultimately, the truth is as it states (Kings I 19:11), “And G-d was not in the Ra’ash (earthquake)” – literally meaning thunderous noise – “and after the thunderous noise there was fire” – i.e. the aspect of the lightning – “but G-d was not in the fire.” Rather, the truth is that the thick darkness itself is good, as it states (Exodus 20:17), “and Moshe approached the thick darkness where G-d was.”