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.
Read kabbalistic (mystical) interpretation of Deuteronomy 23:24: and classical mystical sources.