Jerusalem Talmud Bava Batra 9:8

משנה: וַחֲכָמִים אוֹמְרִים בַּשַּׁבָּת דְּבָרָיו קַייָמִין מִפְּנֵי שֶׁאֵינוֹ יָכוֹל לִכְתּוֹב אֲבָל לֹא בַחוֹל. רִבִּי יְהוֹשֻׁעַ אוֹמֵר בַּשַּׁבָּת אָֽמְרוּ קַל וַחוֹמֶר בַּחוֹל. כַּיּוֹצֵא בוֹ זָכִין לַקָּטָן וְאֵין זָכִין לַגָּדוֹל. רִבִּי יְהוֹשֻׁעַ אוֹמֵר לַקָּטָן אָֽמְרוּ קַל וַחוֹמֶר לַגָּדוֹל. MISHNAH: But the Sages say, on the Sabbath, his words are confirmed¹¹³Even though on the Sabbath one is not permitted to change ownership actively or passively. since he cannot write, but not on weekdays. Rebbi Joshua says, they said that for the Sabbath, so much more for weekdays¹¹⁴He accepts oral wills in all cases, provided that the statement was made before two unrelated witnesses in good standing and able to confirm the distribution in court..
Similarly, one may acquire for an underage person¹¹⁵He has no “hand” in the legal sense. A third person may accept gifts on his behalf and thereby effectuate the transfer of ownership. but not for an adult. Rebbi Joshua says, they said that for an underage person, so much more for an adult¹¹⁶Since it is a generally accepted principle that “one may act for the benefit of a person in his absence and without his knowledge, but not to his detriment.”.

הלכה: וַחֲכָמִים אוֹמְרִים בַּשַּׁבָּת דְּבָרָיו קַייָמִין כול׳. אִית תַּנָּיֵי תַנֵּי וּמַחֲלִיף. רִבִּי יְהוֹשֻׁעַ בֶּן לֵוִי אָמַר. כֵּינִי מַתְנִיתָא. אִם בַּשַּׁבָּת אָֽמְרוּ קַל וַחוֹמֶר בַּחוֹל. אִית תַּנָּיֵי תַנֵּי וּמַחֲלִיף. רִבִּי יְהוֹשֻׁעַ בֶּן לֵוִי אָמַר. כֵּינִי מַתְנִיתָא. אִם בַּקָּטָן אָֽמְרוּ קַל וַחוֹמֶר בַּגָּדוֹל. HALAKHAH: “But the Sages say, on the Sabbath, his words are confirmed,” etc. Some Tannaїm state it inversely¹¹⁷In Tosephta 10:12 and Babli 156b, R. Meїr is reported in R. Eliezer’s name to hold that one may orally dispose of one’s property on a weekday but not on the Sabbath, and that one may acquire for an adult without his knowledge but not for an underage person. The text of the Mishnah there is attributed to R. Jehudah. In either case, it is presumed that a third person be available to formally accept the distribution for the beneficiaries. R. Joshua ben Levi confirms the text of the Mishnah, rejecting the Tosephta.. Rebbi Joshua ben Levi said, so is the Mishnah: if they said that for the Sabbath, so much more for weekdays. Some Tannaїm state it inversely¹¹⁷In Tosephta 10:12 and Babli 156b, R. Meїr is reported in R. Eliezer’s name to hold that one may orally dispose of one’s property on a weekday but not on the Sabbath, and that one may acquire for an adult without his knowledge but not for an underage person. The text of the Mishnah there is attributed to R. Jehudah. In either case, it is presumed that a third person be available to formally accept the distribution for the beneficiaries. R. Joshua ben Levi confirms the text of the Mishnah, rejecting the Tosephta.. Rebbi Joshua ben Levi said, so is the Mishnah: if they said that for an underage person, so much more for an adult.