What is "Hechra Hechratani"?
Metzudas Tziyon: It is an expression of Keri'ah (bowing) and falling. Rashi - the Tov is due to the feminine, like "Libavtani Achosi Kalah" (Shir ha'Shirim 4:9).
What is "b'Ochrai"?
Rashi: [You caused that] all my blood is clouded; you cut off my legs.
A vow to offer a person for an Olah is invalid!
R. Yochanan (in Bereishis Rabah 60:3): He was obligated to buy animal(s) for her value, and offer them for Olos. (He erred to think that he must offer her herself.)
Reish Lakish (in Bereishis Rabah 60:3): He was exempt even from money.
Ramban (Vayikra 27:29): The king, or the Great Sanhedrin in front of all of Yisrael, can make a Cherem (a) to destroy a city; (b) to forbid something, and one who transgresses is Chayav Misah. Sha'ul sentenced his son Yonason to death for contravening his Cherem (Shmuel 1:14:45). Yiftach thought that his Neder applied to his daughter as well. Really, the Cherem applies only to one who rebels.
Why can he not retract? He can permit his vow!
Bereishis Rabah (60:3): Pinchas said, he needs me [to permit his vow]. He should come to me 1 ! Yiftach said, I am the leader - will I go to Pinchas?! Amidst their adamancy, she was lost 2 , and they were punished (refer to 12:7:1:1 and the note there).
Maharam Mintz (79): A vow made at a time of distress, we do not permit it, due to danger. Yam Shel Shlomo (Gitin 4:40) - i.e. if he permits it, the danger is prone to return; perhaps the salvation was only due to the vow! 3
Malbim (35, 36): Indeed, he wanted to permit his vow. He said this in astonishment - can I not retract? Her reply convinced him unlike this.
Chomas Anach (Matos 3): How could Pinchas err to do so?! Kli Yakar (Bamidbar 30:3) says that a Chacham or Beis Din can permit Nedarim, because a person accepts their authority, and wants his vow to be valid only if they consent; this is why a husband can annul his wife's vows. Since Yiftach considered himself more important that Pinchas, Pinchas could not permit him. Why was Pinchas punished? He should have gone to Yiftach, and explained 'to permit your vow, you must humble yourself and come to me.'
Yad David (Ta'anis 4a): This is difficult. Was there no one else who knew to permit a vow other than Pinchas?! (Refer to 12:37:2:2 and the note there.) Torah ha'Temimah (Sof Milu'im, b'Sof ha'Sefer - one can permit based on regret due to the severity of vows, but the Chacham needs Ru'ach ha'Kodesh to know that this is true. Since he did not use his Ru'ach ha'Kodesh for this, he lost it. (Normally, Chachamim permit without Ru'ach ha'Kodesh. Perhaps here, there was concern lest he lie to save his daughter. - PF)
