XLVI. To Catechumens.
In few words, I admonish all believers in Christ, who have forsaken idols, for your salvation. In the first times, if in any way you fall into error, still, when entreated, do you leave all things for Christ; and since you have known God, be a recruit good and approved, and let virgin modesty dwell with you in purity. Let the mind be watchful for good things. Beware that you fall not into former sins. In baptism the coarse dress of your birth is washed. For if any sinful catechumen is marked with punishment, let him live in the signs of Christianity, although not without loss. The whole of the matter for you is this, Do you ever shun great sins.
Source: Writings (New Advent)