Parshah Shavuot

And G-d came down on Mount Sinai (Exodus 19:20)

Once there was a king who decreed: "The people of Rome are forbidden to go down to Syria, and the people of Syria are forbidden to go up to Rome." Likewise, when G-d created the world, He decreed: "The heavens are G-d's, and the earth is given to man" (Psalms 115:16). But when He gave the Torah to Israel, He rescinded His original decree, and declared: "The lower realms may ascend to the higher realms, and the higher realms may descend to the lower realms. And I Myself will begin..."

(Midrash Tanchuma)