Does divorce occur with the phrase "You are my sister," and is it ẓihār? What is the ruling on a husband saying "My wife is thrice divorced" if neither his wife nor anyone else hears it? And can the husband take his wife back in this case?

Scholars have divided Dhihar into explicit (sarih) and allusive (kinayah). The explicit form is that in which the back (zahr) or any other limb is mentioned, and it is considered Dhihar without needing intention. As for the allusive form, it is that which could mean Dhihar or something else, such as a man saying to his wife: "You are like my mother or my sister." This depends on the husband's intention; if he intended Dhihar by it, then it is Dhihar, otherwise not. If a man divorces his wife three times in one go, she becomes irrevocably separated from him (baynunah kubra), and she is not lawful for him until she marries another husband.