In order to halakhically annul a vow, Beis Din must either come up with a reason that you “regretted” having made it, known as “charata”, or that there was a certain circumstance that you were unaware of which, had you known, you would not have vowed, known as “pesach”.  There are nuances to this which we will discuss in upcoming essays (See Shulkhan Arukh YD 228.) 

Our Gemara on Amud Aleph tells us that one angle used to annul a vow is to ask the person, “Had you known that when you make a vow they open your record book in heaven and examine your actions, would you have vowed?”

We may understand this as a legalism which is used to induce a legitimate clause of an unforeseen reality that he was unaware of that makes the oath. This makes the oath technically under false pretenses, so the Beis Din can annul it.

There is a problem with this formulation. It implies that the heavenly accounting book is only open as a result of the vow. However this seems to contradict a Mishna in Avos (3:16) which states that the Heavenly Books are always open and recording. As it were, “This conversation is being recorded for quality assurance purposes.”

הוּא הָיָה אוֹמֵר, הַכֹּל נָתוּן בְּעֵרָבוֹן, וּמְצוּדָה פְרוּסָה עַל כָּל הַחַיִּים. הַחֲנוּת פְּתוּחָה, וְהַחֶנְוָנִי מֵקִיף, וְהַפִּנְקָס פָּתוּחַ, וְהַיָּד כּוֹתֶבֶת, וְכָל הָרוֹצֶה לִלְווֹת יָבֹא וְיִלְוֶה, וְהַגַּבָּאִים מַחֲזִירִים תָּדִיר בְּכָל יוֹם, וְנִפְרָעִין מִן הָאָדָם מִדַּעְתּוֹ וְשֶׁלֹּא מִדַּעְתּוֹ, וְיֵשׁ לָהֶם עַל מַה שֶּׁיִּסְמֹכוּ, וְהַדִּין דִּין אֱמֶת, וְהַכֹּל מְתֻקָּן לַסְּעוּדָה:  

He used to say: everything is given against a pledge, and a net is spread out over all the living; the store is open and the storekeeper allows credit, but the ledger is open and the hand writes, and whoever wishes to borrow may come and borrow; but the collectors go round regularly every day and exact dues from man, either with his consent or without his consent, and they have that on which they [can] rely [in their claims], seeing that the judgment is a righteous judgment, and everything is prepared for the banquet.

If one carefully examines the text we can resolve the contradiction.  The Mishna in Avos refers to an open ledger recording actions. Our Gemara adds an additional clause, “examine your actions”, which in Hebrew is “וּמְמַשְׁמְשִׁין בְּעוֹבָדָךְ”.  This phrase, “Mishmush” or examination, has a particular Talmudic meaning.

Talmud Eiruvin (13b) declares:

תָּנוּ רַבָּנַן: שְׁתֵּי שָׁנִים וּמֶחֱצָה נֶחְלְקוּ בֵּית שַׁמַּאי וּבֵית הִלֵּל. הַלָּלוּ אוֹמְרִים: נוֹחַ לוֹ לְאָדָם שֶׁלֹּא נִבְרָא יוֹתֵר מִשֶּׁנִּבְרָא, וְהַלָּלוּ אוֹמְרִים: נוֹחַ לוֹ לְאָדָם שֶׁנִּבְרָא יוֹתֵר מִשֶּׁלֹּא נִבְרָא. נִמְנוּ וְגָמְרוּ: נוֹחַ לוֹ לְאָדָם שֶׁלֹּא נִבְרָא יוֹתֵר מִשֶּׁנִּבְרָא, עַכְשָׁיו שֶׁנִּבְרָא — יְפַשְׁפֵּשׁ בְּמַעֲשָׂיו. וְאָמְרִי לַהּ: יְמַשְׁמֵשׁ בְּמַעֲשָׂיו.

The Sages taught the following baraisa: For two and a half years, Beis Shammai and Beis Hillel disagreed. These say: It would have been preferable had man not been created than to have been created. And those said: It is preferable for man to have been created than had he not been created. Ultimately, they were counted and concluded: It would have been preferable had man not been created than to have been created. However, now that he has been created, he should examine his actions. And some say: He should scrutinize his actions.

These terms are difficult to translate. One is “Mishmush”, and the other is “Pishpush”. (In Hebrew when there is a repetition in a word it means something continuous or cyclical.  So whether the term is pishpush or mishmush it certainly implies a continuous an ongoing process of self-introspection.)  Regardless, here is how Mesilas Yesharim (3) differentiates between the terms:

כי הנה הפשפוש במעשים הוא לחקור על כלל המעשים ולהתבונן בו, הנמצא בהם מעשים אשר לא יעשו אשר אינם הולכים על פי מצות ה' וחקיו, כי כל אשר ימצא מאלה יבערם מן העולם. 

“Examining" (pishpush) of deeds is to investigate generally one's deeds and inspect them to see whether they contain deeds which one does not do, namely, that are not in line with the commandments of G-d and His statutes. All that he finds of these, he should eradicate them from the world.

אך המשמוש היא החקירה אפילו במעשים הטובים עצמם, לחקור ולראות היש בענינם איזה פניה אשר לא טובה או איזה חלק רע שיצטרך להסירו ולבערו.

"Feeling out" (mishmush) of deeds, on the other hand, is investigation even on the good deeds themselves to inspect and see if they contain any leaning which is not good or any evil component which he needs to remove and eradicate.

We see clearly that Mishmus is more extensive and deeper, looking at even good deeds to see if they are pure enough.

Now we can see what our Gemara means. Vows arouse an extra degree of scrutiny, beyond a mere recording of the deeds in the notebook.  Vows induce a heavenly audit of deeds at their deepest level of motivation, which of course can bring trouble, as who is so righteous as to be utterly pure in intention?