The Shulchan Aruch · Yoreh De'ah
יורה דעה רי״טYoreh De'ah 219
Siman 219 of 402 in Yoreh De'ah — 3 se'ifim
Se’if 1א׳
מִי שֶׁנָּדַר, אוֹ נִשְׁבַּע, לִשָּׂא אִשָּׁה אוֹ לִקְנוֹת בַּיִת וְכַיּוֹצֵא בוֹ, וְלֹא קָבַע זְמַן, אֵין מְחַיְּבִין אוֹתוֹ לִשָּׂא אוֹ לִקְנוֹת, עַד שֶׁיִּמְצָא הָרָאוּי לוֹ.
One who vowed, or swore, to marry a woman or to buy a house and the like, and did not fix a time — they do not compel him to marry or to buy until he finds what is fitting for him.
Se’if 2ב׳
הַנִּשְׁבַּע לִשְׂכֹּר מְלַמֵּד לִבְנוֹ עַד עֲשָׂרָה לִטְרִין, כָּל זְמַן שֶׁיִּשְׂכֹּר מְלַמֵּד הָגוּן הוּא פָּטוּר; וְיִזָּהֵר שֶׁלֹּא יִשְׁלַח הַמְלַמֵּד הָרִאשׁוֹן, עַד שֶׁיָּבֹא הַשֵּׁנִי. כִּי צָרִיךְ לִשְׂכֹּר הַמְלַמֵּד הָרִאשׁוֹן הֶהָגוּן לוֹ, אִם לֹא שֶׁבָּא לוֹ מְלַמֵּד אַחֵר (תְּשׁוּבַת הָרַשְׁבָּ"א).
One who swore to hire a teacher for his son up to ten litras — so long as he hires a fitting teacher, he is exempt. And he shall be careful not to dismiss the first teacher until the second comes; for he must hire the first teacher, who is fitting for him, unless another teacher has come to him (a responsum of the Rashba).
Se’if 3ג׳
מִי שֶׁאָסַר דָּבָר אֶחָד עָלָיו בְּלֹא זְמַן, אָסוּר בּוֹ לְעוֹלָם.
One who forbade one thing upon himself without a time is forbidden in it for ever.
Shulchan Aruch, Yoreh De'ah — Torat Emet 357 edition, via Sefaria — public domain
English rendered from the Hebrew for this app — The Gematria's own rendering program. A rendering of the words, not a ruling; practical halacha is learned with a rav