We have a tendency to think ourselves pretty decent individuals. We see the low-lifes who are paraded across newscasts, and we shake our head at the latest antics of our neighbors and relatives, and we move forward in the unconscious glow of our own decent living.
But the truth is, we are scoundrels before God, guilty of a thousand sins, and none of our "good works" can expunge our record of even one of those sins.
Our tendency toward self-delusion in this area is comparable to the brilliance of the stars vs. the brilliance of the sun. John Calvin writes: "For if the stars, which seem so very bright at night, lose their brilliance in the sight of the sun, what do we think will happen even to the rarest innocence of man when it is compared with God's purity?" (Institutes 3.12.4)
To use another illustration, we easily, almost automatically, construct a pleasant and peaceful--yet empty--righteousness for ourselves that God's judgment will soon shake from us, "just as great riches heaped up in a dream vanish upon awakening." (Ibid.)
Our only hope is Christ. Our only firm ground is before the cross. We have no hope in the Judgment unless we have Christ's righteousness.
Abandon all hope of making yourself look good before God. Trust Christ, cling to him, and put your faith in his wounds.
Bernard of Clairvaux: "Where, in fact, are safe and firm rest and security for the weak but in the Savior's wounds? The mightier he is to save, the more securely I dwell there.... I have sinned a grave sin. My conscience is disturbed, but it will not be perturbed because I shall remember the Lord's wounds." (quoted in Calvin's Institutes 3.12.3)