David sinned and was shamed. "My sin," he said, "is ever before me" (Psa. 51:3). Paul never forgot his days as a tormentor and persecutor. Because of his awful past, he thought himself unfit to be called an apostle (1 Cor. 15:9). Did Peter ever forget having cursed and sworn that he did not know Jesus? I think not.
If this is your sad plight, perhaps the following story will help you. Years ago, two brothers were caught and condemned for stealing sheep. As part of their punishment, their foreheads were branded with large capital letters, "S. S."
One of the young men could not bear the stigma. He fled from town to town, but everywhere he went, people inquired about the letters on his forehead. Haunted by his past, he lived on the run as a fugitive, trying to escape his shame and reproach. He died while still a young man, never able to escape the letters seared into his skin and scorched into his condemning conscience.
Meanwhile, his brother settled down in the same community where his crime had been committed. He worked and lived an honest, upright life. He devoted himself to helping and serving others. Many years past and people scarcely noticed the scars on his face. One day, a stranger moved into town and asked his neighbor about the letters, "S. S." on "that old man's face."
"Well, we're not for certain," his neighbor replied, "but we think it means that he's the Savior's Servant."
So, my dear fellow, suffering servant, however grievous your sins have been, if they are forgiven, you are now wearing the brand of the Savior's Servant. Hence, you may humbly forget those things which are behind and reach forth unto those things which are before, pressing toward the mark for the prize of the high calling of God which is in Christ Jesus our Lord (Phil. 3:13, 14).