Musannaf Ibn Abi Shaybah

Ibrahim (may Allah have mercy on him) says that if a man has two wives, and he forbids one from going out, but the other wife goes out—the one whom he did not forbid—then he assumes that the one who was forbidden has gone out, so he says, "O so-and-so! Did you go out? You are divorced." In this case, both will be divorced: the one whose name was mentioned, because of her name being mentioned, and the other because he said, "You are divorced."