四分律刪繁補闕行事鈔 1.135

1.135

若為說戒，懺悔滅罪，必須清淨。以有犯者，不得說戒，不得聞戒，不得向犯者懺悔，犯者不得受他解罪故也。

If it is for upoṣadha recitation or repentance to eradicate offenses, they must be pure. This is because one who has transgressed may neither recite the precepts nor listen to the precepts, may not receive confession from an offender, nor may the offender receive another's absolution of offenses.