As human beings we have a strong tendency to have an exalted view of our own character, and we flatter ourselves. But a Christian is one who, by the mercy of God, has cast aside all high views of his own character and righteousness. The beginning, middle and end of his hope is found, not in himself, but in the righteousness of Another. He is not one who thinks he is more righteous than others but, exactly the opposite, he is one who, by the grace of God, recognizes he is not righteous. But thanks be to God for His mercy, Jesus comes not to condemn, but to forgive all who acknowledge the truth that they are ill-deserving sinners and whose only credential on their resumes (for acceptance by God) is Christ.
This is perhaps the greatest difference that God has made between the Christian and the non-Christian. The non-Christian either 1) is attempting to work their way to heaven or 2) one who thinks presumptuously that, if there is a God, then they are already good enough to get in or 3) they don't care. In the first two instances they are trusting in their own righteousness. In the last instance, they have abandon themselves to their sin and corruptions. The Christian, in contrast, is one who has beheld the beauty and holiness of God and knows he is undone and no more deserving of heaven than anyone on earth ... and knows, in truth, that he is justly deserving of God's displeasure and that his only hope is in God's mercy toward Him in Christ.