סימן סז סעיף א
אַל תְּהִי רָגִיל בִּנְדָרִים. כָּל הַנּוֹדֵר, כְּאִלּוּ בּוֹנֶה בָּמָה בִּשְׁעַת אִסּוּר הַבָּמוֹת. וְהַמְקַיְמוֹ, כְּאִלּוּ הִקְרִיב עָלֶיהָ קָרְבָּן, שֶׁחַיָּב מִשּׁוּם שְׁחוּטֵי חוּץ, כִּי טוֹב יוֹתֵר שֶׁיִּשְׁאַל עַל נִדְרוֹ וְיַתִּירוּ לוֹ. וַהֲנֵּי מִלֵּי בִּשְׁאָר נְדָרִים. אֲבָל נִדְרֵי הֶקְדֵּשׁ, מִצְוָה לְקַיְמָן, שֶׁנֶּאֱמַר נְדָרַי לַה' אֲשַׁלֵּם. וְלֹא יִשְׁאַל עָלָיו אֶלָּא בִּשְׁעַת הַדְּחָק (ר"ג, ר"ל).
Do not form the habit of making vows. Whoever makes a vow, [it is considered] as if he built an altar at a time that [private] altars were prohibited.1Just as one who sets up his own altar assumes that he is performing the will of God beyond the call of duty, so too, one who vows to prohibit on himself that which is permissible is under the same mistaken impression. One who fulfills [such a vow is considered] as though he had offered a sacrifice upon it, which makes him guilty of shechutei chutz.2The prohibition of slaughtering sacrifices outside the Bais Hamikdash. Rather it is preferable that you request absolution from your vow3One who makes a vow may petition the Beis Din (Court) to absolve him of his vow. This is usually based on his claim that had he been aware of certain consequences he never would have made the vow in the first place. If the Beis Din (Court) agrees, it may absolve him. and that the Beis Din (Court) nullify it for you. This applies only to ordinary vows, but vows made to the sanctuary4I.e. vows to donate to worthy causes. are meritorious to fulfill, for it is said: "I will fulfill my vows to Hashem,"5Psalms 116: 14. and one should not attempt to annul these vows unless the need is great.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)