Musar for Taanit 31:21

The fourteenth principle of repentance is the confession, as it is said, "That he shall confess that wherein he hath sinned" (Lev. 5:5). And a person is obliged to remember his sins, and the sins of his fathers. Now why should he confess the sins of his fathers? Because of the fact that he is considered guilty if he clings to the evil deeds of his fathers. And thus it is written, "And they shall confess their iniquity and the iniquity of their fathers" (Lev. 26:40). And he should be very careful at the time of the confession to resolve in his heart to abandon his evil ways, for if he returns to them and does not abandon them he is like one who immerses himself but grasps an unclean creature (Ta'anith 16a). For confession is like immersion and the sin is like the unclean worm, and it is clear that immersion is of no use when the person who immerses himself holds on to the source of his defilement.