True penance is not to commit things worthy of repentance but to lament what has been committed.
cf. Ambr. De Quadrag. Serm. 9, Greg. Magn. Homil. in Evang. ii. 34. 15But since this is annulled by the weakness of many, not to say of all, the measures of penance must be known. And thus a scheme of these has been handed down by the holy fathers, so that in accordance with the greatness of the offences the length also of the penances should be ordained.