Nedarim7: 9
,,שֶׁאַתְּ נֶהֱנֵית לִי עַד הַפֶּסַח אִם תֵּלְכִי לְבֵית אָבִיךְ עַד הֶחָג”, הָלְכָה לִפְנֵי הַפֶּסַח — אֲסוּרָה בַּהֲנָאֲתוֹ עַד הַפֶּסַח. אַחַר הַפֶּסַח, בְּלֹא יַחֵל דְּבָרוֹ. ,,שֶׁאַתְּ נֶהֱנֵית לִי עַד הֶחָג אִם תֵּלְכִי לְבֵית אָבִיךְ עַד הַפֶּסַח”, וְהָלְכָה לִפְנֵי הַפֶּסַח — אֲסוּרָה בַהֲנָאָתוֹ עַד הֶחָג; וּמֻתֶּרֶת לֵילֵךְ אַחַר הַפֶּסַח.
[If a person said: “Konam] whatever benefit you have from me before Pesach, if you go to your father's house before the Festival” —- if she went before Pesach, she is forbidden to have any benefit from him until Pesach; [if she went] after Pesach, [she is liable for] “he shall not break his word.” [“Konam] whatever benefit you have from me before the Festival, if you go to your father's house before Pesach” —- if she went before Pesach, she is forbidden to benefit from him until the Festival; but she is permitted to go after Pesach.