I've been fascinated with Isaiah's call (6.1-8) since OT1. It is a beautiful story full of imagery, myth, and legend. It is the call narrative we all wish we had; God with his flowing white robe and angelic attendants in our very presence. It'd make discernment so much easier.
There is one detail that I'm glad I didn't have to experience; the whole live coal to the lips thing sounds less than appealing. But it happens, and then the angel of the Lord says something interesting to Isaiah, "Now that this [coal] has touched your lips, your guilt has departed and your sin is blotted out." Were that it was so easy to have our guilt depart. What the angel is actually saying, of course, is that Isaiah, who was once guilty of sin is now innocent by the grace of God. This state is somewhat foreign to the Hebrews, but is well known to modern Christians. We have been washed clean in the blood of the lamb, as it were. Most of us know that, intuitively. We who were once guilty have had our guilt depart from us.
But most of us know in our hearts that the guilt doesn't go away quite so easily. The feeling bad, the self-loathing, the wishing for a do-over; that seems to stick around long after our guilt has departed.
As we pray this Sunday to be set free, I think a lot of us are really saying, "Oh God, let my guilt, both kinds, depart from me." The first step is to really believe that I who was once guilty am now forgiven, the second is accepting that God's forgiveness wipes the slate clean; that I can't live in the past, but can only be present and, with God's help, change my future for the better. Let God take away your guilt and enjoy the abundance of his grace.