'Daughters in law' in the Bible

they sacrifice upon the tops of the mountains, and burn incense upon the hills, under oak and poplar and terebinth, because the shade thereof is good; therefore your daughters play the harlot and your daughters-in-law commit adultery.

I will not punish your daughters when they play the harlot, nor your daughters-in-law for their committing adultery; for they themselves go aside with harlots, and they sacrifice with prostitutes: and the people that doth not understand shall come to ruin.