This Pasuk teaches us that if the Arus annuls the Neder, it is annulled. What if her father does not annul it?
Rashi: The Torah, in Pasuk 17, inserts the words "bi'Ne'urehah Beis Avihah, which teaches us that as long as she is a Na'arah, she is under her father's jurisdiction. 1 Consequently, if her father does not annul the Neder as well, 2 it remains intact.
Ramban: If also her father does not annul the Neder, it remains intact, 3 because otherwise, why does the Torah need to add "ve'Im Beis Iyshah Nadarah"? 4
Unless she is married, in which case she enters the domain of her husband, as is evident from Pasuk 14.
Rashi: And certainly if either of them specifically endorsesit.
Seforno (on Pasuk 15): Even though he did not verbally uphold it ? because his silence indicates that he condones the Neder.
See Ramban.
What are the implications of "be'Yom Shemo'a Iyshah"?
Nedarim, 77b: It implies all day ? until noghtfall. 1
And the Torah writes ?mi?Yom el Yom? in Pasuk 15, to teach us that one may perform Hafaras Nedarim by night.
What is the definition of "Mivta Sefasehah"?
Targum Onkelos and Targum Yonasan: It means literally what she utters with her lips.
Shevu'os, 20a: Refer to 30:7:3:1 and note.
