מוֹצָ֥א שְׂפָתֶ֖יךָ תִּשְׁמֹ֣ר וְעָשִׂ֑יתָ כַּאֲשֶׁ֨ר נָדַ֜רְתָּ לַיהוָ֤ה אֱלֹהֶ֙יךָ֙ נְדָבָ֔ה אֲשֶׁ֥ר דִּבַּ֖רְתָּ בְּפִֽיךָ׃ (ס)
That which is gone out of thy lips thou shalt observe and do; according as thou hast vowed freely unto the LORD thy God, even that which thou hast promised with thy mouth.
Mishnah Terumot
He who intends saying ‘terumah’ and says ‘tithe’, or ‘tithe’ and says ‘terumah’; ‘Burnt-offering’ and he says ‘peace-offering’, or ‘peace-offering’ and he says ‘burnt-offering’; ‘[I vow] that I will not enter this house,’ and says ‘that house’, ‘That I will not derive any benefit from this [man],’ and says ‘from that [man],’ he has said nothing until his heart and mind are at one.