4וְלָמָּה לֹא חִלְּקוּ בַּשְּׁנִיָּה בֵּין שֶׁהִכִּיר בָּהּ בֵּין שֶׁלֹּא הִכִּיר בָּהּ אֶלָּא אָמְרוּ אֵין לָהּ עִקַּר כְּתֻבָּה בְּכָל מָקוֹם. מִפְּנֵי שֶׁהִיא מִדִּבְרֵי סוֹפְרִים עָשׂוּ בָּהּ חִזּוּק. אֲבָל אִם נָשָׂא אַחַת מֵחַיָּבֵי לָאוִין; וְהִכִּיר בָּהּ. אוֹ אַחַת מֵחַיָּבֵי עֲשֵׂה בֵּין הִכִּיר בָּהּ בֵּין שֶׁלֹּא הִכִּיר בָּהּ יֵשׁ לָהּ כְּתֻבָּה. שֶׁחַיָּבֵי לָאוִין שֶׁהִכִּיר בָּהּ רָצָה לָזוּן בִּנְכָסָיו וְחַיָּבֵי עֲשֵׂה אִסּוּרָן קַל. וְיֵשׁ לִשְׁתֵּיהֶן מְזוֹנוֹת לְאַחַר מוֹתוֹ. וְכֵן אִם לָוְתָה וְאָכְלָה חַיָּב לְשַׁלֵּם. וּכְשֶׁכּוֹפִין אוֹתָן לְהוֹצִיא מוֹצִיאִין מִן הַבַּעַל כָּל פֵּרוֹת שֶׁאָכַל מִכָּל נְכָסֶיהָ:
Why did [our Sages] not distinguish between a sh'niyah [whom her husband] recognized, and one that he did not recognize, but rather said that in all instances she is not entitled to the fundamental requirement of the ketubah? Because [the prohibition involving these relations] is Rabbinic [in origin], they reinforced it. If, by contrast, a man married a woman [whom he was forbidden to marry because of] a negative prohibition of the Torah [that was not punishable by death, neither by the hand of G-d nor by an earthly court] and he was aware of the prohibition, [his wife] is entitled to [the money due her by virtue of her] ketubah.[Similarly, if he marries] a woman whom he was forbidden to marry because of a positive commandment, whether he was aware of the prohibition or not, [his wife is entitled to a ketubah]. [The rationale is] that if he recognized that a woman was forbidden by a negative prohibition, he willingly undertook to damage his resources. And with regard to [relations which are forbidden] because of a positive commandment, the prohibition is light. In both these instances, the women are entitled to support [from their husband's estate] after his death. Similarly, if [during his absence,] they borrowed money for their sustenance, [the husband] is liable to pay. And when the husband is forced to divorce [a woman in either of these situations], he is forced to reimburse her for all the benefit that he received from her property.