Our Gemara on Amud Aleph quotes a verse in Bamidbar (30:7-8):

וְאִם־הָי֤וֹ תִֽהְיֶה֙ לְאִ֔ישׁ וּנְדָרֶ֖יהָ עָלֶ֑יהָ א֚וֹ מִבְטָ֣א שְׂפָתֶ֔יהָ אֲשֶׁ֥ר אָסְרָ֖ה עַל־נַפְשָֽׁהּ׃ 

If she should become someone’s [wife] while her vow or the commitment commitment Lit. “utterance of her lips.” to which she bound herself is still in force,

וְשָׁמַ֥ע אִישָׁ֛הּ בְּי֥וֹם שׇׁמְע֖וֹ וְהֶחֱרִ֣ישׁ לָ֑הּ וְקָ֣מוּ נְדָרֶ֗יהָ וֶֽאֱסָרֶ֛הָ אֲשֶׁר־אָסְרָ֥ה עַל־נַפְשָׁ֖הּ יָקֻֽמוּ׃

and her husband learns of it and offers no objection on the day he finds out, her vows shall stand and her self-imposed obligations shall stand.

The verse uses an unusual phrase, “אִם־הָי֤וֹ תִֽהְיֶה֙ , which is hard to translate but it is something like, “If she shall indeed have been married”. Grammatically, it is close to what we would call in English, a past perfect form. 

Before we go further in this discussion, we need to take a short history lesson.  There is an ancient chain and system of cross verifications within the Torah called “The Mesorah”. Literally, it means the tradition, but actually it is rabbinic scholarly system of cross references, spanning millennia, where certain word forms are noted in how often they repeat themselves, along with occasional mnemonics.  In some older chumashim, you can still see these cryptic notes on the margin, often just a few letters, acronym or abbreviation.  Learning how to decipher them is fun and interesting, but beyond today’s discussion. The goal of these mesorah notes was to allow for verification and maintenance of unusual word structures that could easily have been confused and written incorrectly. This often has to do with which words are written “full” or “missing”, such as “Sukkos” with the letter vav or without a vav.  

The form in this verse, “hayo” “הָי֤וֹ”  which is different than the usual “haya”, or “yihyeh”, or “tihyeh”, is noted by the Mesorah to occur only one other time in Chumash, and that is by Avraham (Bereishis 18:18):

וְאַ֨בְרָהָ֔ם הָי֧וֹ יִֽהְיֶ֛ה לְג֥וֹי גָּד֖וֹל וְעָצ֑וּם וְנִ֨בְרְכוּ־ב֔וֹ כֹּ֖ל גּוֹיֵ֥י הָאָֽרֶץ׃

And Avraham is to become a great and populous nation and all the nations of the earth are to bless themselves by him

Rav Tzvi Elimelech Shapiro (Agra Dekallah) notes the linguistic correspondence between these two verses and suggests that there is also a hint of deeper correspondence.  Hashem’s covenant (marriage – see previous Psychology of the Daf, Nedarim 69) with Avraham also came with pre-existing vows, that is the commitment to make him into a great nation.

Aside from reinforcing the idea of the Jewish Marriage and Marriage of God to the Jewish people, which we have discussed many times (see for example Psychology of the Daf, Yevamos 11), this chiddush also is a powerful indicator of the wisdom and layers of meaning latent within the text of the Torah.  In times of oppression, general illiteracy, and hundreds of years before the printing press, our greatest minds and sages were lovingly guarding and copying sacred texts to preserve them with precision.  Now that isn’t to say, that over the years errors could have crept in, as there are some notable variants within the text of the Torah (a most famous one, was Rash’s extra letter vav, in Shemos 25:22, see Prof Shnayur Z. Leiman’s essay, “Was Rashi’s Torah Scroll Flawed?”  http://www.leimanlibrary.com/texts_of_publications/88.%20Was%20Rashi's%20Torah%20Scroll%20Flawed.pdf ). Nevertheless, we are talking about the most minor of errors, which are halakhically significant, but in the big picture give us great confidence in the validity of our traditions and texts.