1) Isaiah has a vision of God sitting on a throne in the temple after the death of King Uzziah.
2) In the vision, seraphim with six wings surround God's throne calling out "Holy, holy, holy" and the temple is filled with smoke.
3) Isaiah acknowledges his unworthiness in God's presence due to his sinfulness. A seraphim touches Isaiah's lips with a burning coal from the altar, telling him his sins are forgiven.