Insufficient

Isa 6:3-8
3 And one [seraphim] called out to another and said, "Holy, Holy, Holy, is the LORD of hosts, the whole earth is full of His glory."4 And the foundations of the thresholds trembled at the voice of him who called out, while the temple was filling with smoke.5 Then I said, "Woe is me, for I am ruined! Because I am a man of unclean lips, and I live among a people of unclean lips; for my eyes have seen the King, the LORD of hosts."6 Then one of the seraphim flew to me, with a burning coal in his hand which he had taken from the altar with tongs.7 And he touched my mouth {with it} and said, "Behold, this has touched your lips; and your iniquity is taken away, and your sin is forgiven."8 Then 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!"(NAS)

This is a great verse to look at when feeling insufficient. From my VERY limited understanding of what the Hebrew words in verse seven mean, the word translated "taken away" could mean "turn off,' and the word translated "forgiven" means "covered."* From the context, I think it would be fair to say this verse shows that our sin is not only covered, but we no longer have to sin. Our sin is "turned off." We are all sinners. We are incapable of doing anything worthy for God. But, the beauty of grace is that God makes us Holy. By the sacrifice of His Son, we can say to Him, "Here am I. Send me!"

*Strong's Greek/Hebrew Dictionary from PC Study Bible © 1993-1996