Above it stood the seraphims: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly. And one cried unto another, and said, Holy, holy, holy, is the LORD of hosts: the whole earth is full of his glory. And the posts of the door moved at the voice of him that cried, and the house was filled with smoke. Then said I, Woe is me! for I am undone; because I am a man of unclean lips, and I dwell in the midst of a people of unclean lips: for mine eyes have seen the King, the LORD of hosts.
Attending God were celestial beings called seraphim, with four wings for reverence and two wings for service. These celebrate the holiness of God and require that God’s servants be cleansed before serving Him. The vision produced deep conviction of sin in the prophet, then brought him to the place of confession.