Because then there was an annulment of the decree that “The uppers shall not descend below and the lowers shall not ascend above” etc. Just as it was at Matan Torah the first time, so too, is [this annulment operative] constantly [now], through the study of Torah by each and every single one of Yisroel.
Because then: There is a Moshul brought down in Chassidus about a King who ruled over Rome and Syria. He made a decree that those in Rome were not allowed to ascend to Syria, and those in Syria were not allowed to descend to Rome. One day the king decided to annul this decree and allow the peoples from Syria to go to Rome and the citizens of Rome to travel to Syria. So too here at Matan Torah, where until that time the uppers being the Divine energies were prevented from descending into the world and the lowers being the humans were prevented from ascending the upper realms here Hashem annulled the decree and said that He himself will be the first to descend as the Possuk states that Hashem descended upon the mountain.
Annulment: Then and forever.
Decree: That was in place all the way up until Matan Torah.
Uppers: Everything G-dliness.
Lowers: Everything materialistic.
Etc: And from the time of Matan Torah and forever permission has been granted and everyone has been given the Koach both to draw down from above below and also to elevate the lower realm from below to above. In a manner that there is an attachment between them. And the Elokus permeates the materialism of this world and there will be a rectification and purification of the world.
First time: The only time, but the first time of this revelation. In which the revelation was drawn down from above to the world below.
