Isaiah 6:6

"Then flew one of the seraphim unto me, having a live coal in his hand, which he had taken with the tongs from off the altar: and he touched my mouth with it, and said, Lo, this has touched thy lips; and thine iniquity is taken away and thy sin forgiven. And I heard the voice of the Lord saying, Whom shall I send, and who will go for us? Then I said, Here am I; send me."

The forgiveness of Isaiah's sin here was not final and absolute, because the ultimate price of all human redemption from sin had not at that time been paid in the bloody sacrifice of Jesus Christ himself. The meaning is simply that God "passed over" his sins as explained in Romans 3:23-26. Rawlinson observed that the symbolical "forgiveness" achieved here by means of the live coal from off the altar actually demonstrated that (1) sin could indeed be purged; but that the highest supernatural creatures, even one standing before God Himself could alone procure such a forgiveness.[6] If this should be allowed, then the live coal from off the altar would be a symbol of that greater and all-sufficient sacrifice in Christ that the ancient altar typified.

"And thy sin forgiven ..." "This forgiveness was not accomplished by any physical effect of fire to cleanse from sin, but in relation to that altar-sacrifice, of which Messiah in his death was to be the antitype."[7]

God's challenging question, "Whom shall I send, and who will go for us?" raises the problem of who is meant by "us." Some think that God here included members of his heavenly court; but our own view is that we have here exactly the plural that was used when God said, "Let us make man, etc." The Trinity is therefore the most logical answer to the question; but this is not absolutely certain. because, "The plural may merely indicate majesty."[8]