Halakhah for Sanhedrin 151:13

To not reveal the nakedness of the daughter: To not reveal the nakedness of the daughter, and this is not elucidated in the language of the Torah, that the verse would state, "The nakedness of your daughter you shall not reveal." And because of [the following] did a verse not come about it explicitly, since there is no need for it: As since the Torah forbade the daughter of the son and the daughter of the daughter which are more distant than she, there is no reason to say that she is forbidden - as it is an a fortiori argument (kal vachomer). And they, may their memory be blessed, also learned it from a inferential comparison (gezearah shavah). As if we had only extracted it with an fortiori argument, no one would have ever been judged for it - as it is established for us (Sanhedrin 76a) [that] 'we do not punish from an inference.'