The Rambam · Sefer Zeraim
הלכות מתנות עניים ח׳Gifts to the Poor 8
Chapter 8 of 10 in Gifts to the Poor — 18 halachot
Halacha 1א׳
הַצְדָקָה הֲרֵי הִיא בִּכְלַל הַנְּדָרִים. לְפִיכָךְ הָאוֹמֵר הֲרֵי עָלַי סֶלַע לִצְדָקָה אוֹ הֲרֵי סֶלַע זוֹ צְדָקָה חַיָּב לִתְּנָהּ לָעֲנִיִּים מִיָּד וְאִם אִחֵר עָבַר בְּ (דברים כג כב) "בַל תְּאַחֵר" שֶׁהֲרֵי בְּיָדוֹ לִתֵּן מִיָּד וַעֲנִיִּים מְצוּיִין הֵן. אֵין שָׁם עֲנִיִּים מַפְרִישׁ וּמַנִּיחַ עַד שֶׁיִּמְצָא עֲנִיִּים. וְאִם הִתְנָה שֶׁלֹּא יִתֵּן עַד שֶׁיִּמְצָא עָנִי אֵינוֹ צָרִיךְ לְהַפְרִישׁ. וְכֵן אִם הִתְנָה בְּשָׁעָה שֶׁנָּדַר בִּצְדָקָה אוֹ הִתְנַדֵּב אוֹתוֹ שֶׁיִּהְיוּ הַגַּבָּאִין רַשָּׁאִין לְשַׁנּוֹתָהּ וּלְצָרְפָהּ בְּזָהָב הֲרֵי אֵלּוּ מֻתָּרִין:
A [pledge to] tzedakah is a form of a vow, and therefore one who says, "I pledge to give a selah for tzedakah," or "This selah is for tzedakah" is obligated to give it to the poor immediately,144See Babylonian Talmud Rosh Hashanah 6a. and if he delays, then he has transgressed the commandment not to delay [fulfilling a vow] (Deut. 23:22). Thus, if poor people can be found there [when he makes the vow], he should give it [to them] immediately. If there are no poor people there, he should set it aside and leave it until he happens upon some poor people. But if he stipulates that he will not give [the coin] until he encounters a poor person, then he need not set it aside. So also if he makes the condition at the time he took the vow for tzedakah or to donate something that the collectors are permitted to exchange it or to change it with a goldsmith, then they are permitted to do so.
Halacha 2ב׳
הַמַּתְפִּיס בִּצְדָקָה חַיָּב כִּשְׁאָר הַנְּדָרִים. כֵּיצַד. אָמַר הֲרֵי סֶלַע זוֹ כְּזוֹ הֲרֵי זוֹ צְדָקָה. הַמַּפְרִישׁ סֶלַע וְאָמַר הֲרֵי זוֹ צְדָקָה וְלָקַח סֶלַע שְׁנִיָּה וְאָמַר וְזוֹ הֲרֵי שְׁנִיָּה צְדָקָה. וְאַף עַל פִּי שֶׁלֹּא פֵּרֵשׁ:
One who connects pledges of tzedakah is as obligated with one vow as with another. How so? [This applies] if he said, "This selah is like that selah, then that one is for tzedakah." If he sets aside a selah and said, "This is for tzedakah," and then he took out a second selah and said, "And this second one is for tzedakah" even though he did not set it aside from the start.145See Babylonian Talmud Nedarim 7a.
Halacha 3ג׳
הַנּוֹדֵר צְדָקָה וְלֹא יָדַע כַּמָּה נָדַר יִתֵּן עַד שֶׁיֹּאמַר לֹא לְכָךְ נִתְכַּוַּנְתִּי:
One who took a vow for tzedakah without knowing how much he vowed should give until he says, "This is not what I intended."146See Mishnah Menachot 13:4.
Mishneh Torah, Torat Emet 363 edition, via Sefaria — public domain
English: Gifts for the Poor, tr. Joseph B. Meszler, 2003 — CC BY