Isaiah 6:1-3
In the year that King Uzziah died I saw the Lord sitting upon a throne, high and lifted up; and his train filled the temple. Above him stood the seraphim; each had six wings: with two he covered his face, and with two he covered his feet, and with two he flew. And one called to another and said: "Holy, holy, holy is the LORD of hosts; the whole earth is full of his glory."
Isaiah received a call not by reading a treatise on social injustice or the basic elements of Israelite cultic worship, but by a mystical gift and call. He saw, first of all, God's glory, not our depravity. Indeed, only in light of God's glory could he see our depravity–and the hope that lay beyond it in the coming grace of Messiah. Like Isaiah, we only have the courage to face the darkness when we have hope the light is greater.