What does Isaiah 6:7 mean?
Seeing God's glory in the temple has utterly convinced Isaiah that he is unworthy to speak about the Lord's holiness. In fact, Isaiah knows that his sinfulness makes him so unworthy to appear before the Lord that he deserves to die (Isaiah 6:5). The Lord's purpose in revealing Himself to Isaiah was not to judge him for unworthiness. Has plans to use Isaiah as His prophet to His people.One of the "fiery serpent" seraphim angels flies toward Isaiah with a burning-hot coal from the altar of atonement or incense (Isaiah 6:6). He places the coal against Isaiah's mouth. He tells Isaiah that when the coal touched his lips, his personal guilt was taken away and his sin paid for.
The word "atone" means to make amends or reparation. In other words, Isaiah's sin was covered by the fire from the alter where Israel sacrificed the animals to receive atonement on a national level. With his sin set aside, Isaiah was free to be used by the Lord to give God's word to his people.