Genesis 19:35

וַתַּשְׁקֶיןָ אֶת־אֲבִיהֶן יַיִן בַּלַּיְלָה הוּא וַתָּבֹא הַבְּכִירָה וַתִּשְׁכַּב אֶת־אָבִיהָ וְלֹֽא־יָדַע בְּשִׁכְבָהּ וּבְקׄוּמָֽהּ

And they made their father drink wine that night. And the first-born went in, and lay with her father; and he knew not when she lay down, nor when she arose.

וַֽיְהִי מִֽמָּחֳרָת וַתֹּאמֶר הַבְּכִירָה אֶל־הַצְּעִירָה הֵן־שָׁכַבְתִּי אֶמֶשׁ אֶת־אָבִי נַשְׁקֶנּוּ יַיִן גַּם־הַלַּיְלָה וּבֹאִי שִׁכְבִי עִמּוֹ וּנְחַיֶּה מֵאָבִינוּ זָֽרַע

And it came to pass on the morrow, that the first-born said unto the younger: ‘Behold, I lay yesternight with my father. Let us make him drink wine this night also; and go thou in, and lie with him, that we may preserve seed of our father.’

וַֽתַּהֲרֶיןָ שְׁתֵּי בְנֽוֹת־לוֹט מֵאֲבִיהֶֽן

Thus were both the daughters of Lot with child by their father.

וַתֵּלֶד הַבְּכִירָה בֵּן וַתִּקְרָא שְׁמוֹ מוֹאָב הוּא אֲבִֽי־מוֹאָב עַד־הַיּֽוֹם

And the first-born bore a son, and called his name Moab—the same is the father of the Moabites unto this day.