Jerusalem Talmud Bava Kamma 10.5

משנה: שָׁטַף נָהָר חֲמוֹרוֹ וַחֲמוֹר חֲבֵירוֹ שֶׁלּוֹ יָפֶה מְנָה וְשֶׁל חֲבֵירוֹ מָאתַיִם הִנִּיחַ אֶת שֶׁלֹּוֹ וְהִצִּיל אֶת שֶׁל חֲבֵירוֹ אֵין לוֹ אֶלָּא שְׂכָרוֹ. אִם אָמַר אַצִּיל אֶת שֶׁלָּךְ וְאַתָּה נוֹתֵן לִי דְמֵי שֶׁלִּי חַיָיב לִיתֵּן לוֹ.

MISHNAH: If a river washed away his donkey and another’s donkey; his was worth a mina, the other’s 200. If he abandoned his own and saved the other’s, he only has his wages. But if he said, I shall save yours if you pay me the value of mine, he is liable to pay him.

הלכה: שָׁטַף נָהָר אֶת חֲמוֹרוֹ כול׳. תַּנֵּי. הִנִּיחַ שֶׁלֹּוֹ לְהַצִּיל שֶׁלַּחֲבֵירוֹ וְעָלָה שֶׁלַּחֲבֵירוֹ מֵאֵילָיו אֵין נִזְקַק לוֹ כְּלוּם. אֶלָּא הִנִּיחַ שֶׁלֹּוֹ לְהַצִּיל שֶׁלַּחֲבֵירוֹ וְעָלָה שֶׁלּוֹ מֵאֵילָיו. מָהוּ דְיֵימַר לוֹ. נִתְיָיאַשְׁתִּי. נִישְׁמְעִינָהּ מֵהֲדָא. שָׁטַף נָהָר חֲמוֹרוֹ וְהָיָה צָוַוח וְאוֹמֵר. לֹא נִתְיָיאַשְׁתִּי. רֵישׁ לָקִישׁ אָמַר. כָּל זְמַן שֶׁצָּוַוח לֹא נִתְיָיאַשׁ. רִבִּי יוֹחָנָן אָמַר. חֲזָקָה מְיָיאֵשׁ הוּא.

HALAKHAH: “If a river washed away his donkey,” etc. It was stated: If he abandoned his to save the other’s, but the other’s climbed out by himself, he does not owe him anything. But if he abandoned his to save the other’s, and his own climbed out by himself, may he say, “I did not abandon hope of recovery”? Let us hear from the following: If a river washed away his donkey and he was crying: “I did not abandon hope of recovery!” Rebbi Simeon ben Laqish said, as long as he is crying he did not abandon hope of recovery. Rebbi Joḥanan said, there is a presumption that he had abandoned hope.