This afternoon I read one of the most beautiful sermons by Edwards I've ever read, "Great Guilt No Obstacle to the Pardon of the Returning Sinner."
It is based on Ps 25:11 - "For the sake of your name, O Lord, pardon my iniquity, for it is great." I expected him to extrapolate on the first third of that verse - "for the sake of your name." That would have been typical Edwards. But he doesn't. He fixes his gaze on the last third - "for it is great." He reflects at length on the remarkable prayer David makes here. The prayer is not "Forgive my iniquity, for it is small," or "forgive my iniquity, in spite of the fact that it is great." But "forgive my iniquity for it is great."
The recognition that I am exceedingly guilty before God is not a hindrance to coming to him, but is, oddly, the very basis that makes my coming to him meaningful. I find that extremely liberating.
God allows such a plea as this: for he is moved to mercy towards us by nothing in us but the miserableness of our case. He doth not pity sinners because they are worthy, but because they need his pity. (Works, Hickman ed., 111)
You need not be at all the more fearful of coming because of your sins, let them be ever so black. If you had as much guilt lying on each of your souls as all the wicked men in the world, and all the damned souls in hell; yet if you come to God for mercy, sensible of your own vileness, and seeking pardon only through the free mercy of God in Christ, you would not need to be afraid; the greatness of your sins would be no impediment to your pardon. . . . If you are but willing, you may freely come and unload yourselves, and cast all your burdens on Christ, and rest in him. (p. 112)