Isaiah 6:2-4

Above Him seraphim (heavenly beings) stood; each one had six wings: with two wings he covered his face, with two wings he covered his feet, and with two wings he flew. And one called out to another, saying, “Holy, Holy, Holy is the LORD of hosts; The whole earth is filled with His glory.” And the foundations of the thresholds trembled at the voice of him who called out, and the temple was filling with smoke.