Mishnayos Gittin Perek 6 Mishnah 6

With regard to one who was thrown into a pit and thought that he would die there, and he said that anyone who hears his voice should write a bill of divorce for his wife, and he specified his name, her name, and all relevant details, those who hear him should write this bill of divorce and give it to his wife, even though they do not see the man and do not know him. A healthy man who said: Write a bill of divorce for my wife, but did not say to give it to her, presumably sought to mock her. Since he told them to write the bill of divorce and not to give it, it is not a valid bill of divorce. The mishna relates: There was an incident involving a healthy man who said: Write a bill of divorce for my wife, and then ascended to the roof and fell, and died. Rabban Shimon ben Gamliel said: If he fell at his own initiative, taking his own life, it is a valid bill of divorce, as it is clear that he anticipated his death and instructed those listening to write the bill of divorce with the intent of giving it to her. However, if the wind forced him to fall, it is not a valid bill of divorce, as there was no clear intent to give her the bill of divorce.

מִי שֶׁהָיָה מֻשְׁלָךְ לְבוֹר וְאָמַר, כָּל הַשּׁוֹמֵעַ אֶת קוֹלוֹ יִכְתֹּב גֵּט לְאִשְׁתּוֹ, הֲרֵי אֵלּוּ יִכְתְּבוּ וְיִתֵּנוּ. הַבָּרִיא שֶׁאָמַר, כִּתְבוּ גֵט לְאִשְׁתִּי, רָצָה לְשַׂחֶק בָּהּ. מַעֲשֶׂה בְּבָרִיא אֶחָד שֶׁאָמַר, כִּתְבוּ גֵט לְאִשְׁתִּי, וְעָלָה לְרֹאשׁ הַגַּג וְנָפַל וּמֵת. אָמַר רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל, אָמְרוּ חֲכָמִים, אִם מֵעַצְמוֹ נָפַל, הֲרֵי זֶה גֵט. אִם הָרוּחַ דְּחָאַתּוּ, אֵינוֹ גֵט: