Shaarei Teshuvah
The seventh level is the severity of excision: The punishment that one is liable [when the consequence of the sin’s] wanton [transgression] is excision; when inadvertent, is for one to bring a sin-offering. And so did our Rabbis, may their memory be blessed, say (Keritot 2a) - that a person is only liable to bring a sin-offering for something the punishment of which, when done wantonly, is excision. [This is] like the matter that is stated (Leviticus 20:20), “they shall bear their guilt; they shall die childless.” And there are two categories of those liable for excision: