Why does the Torah insert "Motzei Sefasecha Tishmor Ve'asisa "?
Rashi: To add an Asei to the Lo Sa'aseh (of "Lo Se'acher Leshalmo" - in the previous Pasuk). 1
Ramban (in Pasuk 23): Refer to 23:24:1:1. 'In any event, having made the Neder, make sure to keep everything that you promised - and do not think that you will receive reward for your good intentions when making the Neder, even if you don't manage to carry it out'. 2
Rosh Hashanah 6a: We learn an Asei from "Motzei Sefasecha" and a Lo Sa'aseh from "Tishmor". 3
Yerushalmi Rosh Hashanah, 1:1: "Ve'asisa" has connotations of forcing, implying that Beis-Din force the person who is delaying his Neder by taking from him a security until he brings it. 4
Gur Aryeh ? Presumably, we learn it from "Ve'asisa" in the current Pasuk. Because even though it teaches us that Beis-Din force people, if it came only for that, it should have said 'Ve'asucha'!
Ramban: As Shlomoh ha'Melech said in Koheles, 5:3 & 4. See Ramban and R. Chavel's notes.
See Torah Temimah, note 124.
See Torah Temimah, note 126.
Is a person Chayav to fulfill a Neder that he thinks but does not verbalize?
Refer to Sh'mos, 35:22:1.1:2 and note.
What is the difference between a Neder and a Nedavah (in the realm of Hekdesh)?
Kinim 1:1: "Neder" is where the person says 'Harei alai ... ', which is a personal undertaking to bring a Korban; 1 "Nedavah", where he says 'Harei Zu ... ', declaring the animal Hekdesh. 2
Kinim 1:1: A Neder is subject to Achrayus - If the animal that he subsequently chooses gets lost or dies, he is obligated to replace it), but a Nedavah does not.
And bringing it immediately as a Korban in order to avoid sinning - that is the ideal way to bring a voluntary Korban. See Oznayim la'Torah.
Why does the Torah insert the latter part of the Pasuk ? from "Ka'asher Nadarta" and onwards ? which is seemingly superfluous?
Rosh Hashanah, 6a: "Ka'asher Nadarta" ? 'Zeh Neder': "la'Hashem Elokecha" ? 'Eilu Chatamos va'Ashamos, Olos u'Shelamim'; "Nedavah" ? kee'Mashma'ah'; "asher Dibarta" ? 'Eilu Kodshei Bedek ha'Bayis'; "be'Ficha" ? 'Zu Tzedakah', 1 all of which are subjet to 'Bal Te'acher'.
See Torah Temimah, note 128.
Seeing as the Torah is discussing a Neder, why does it add the word "Nedavah"?
Zevachim, 2b: To teach us that, if the Neder is Shechted li'Shemah (in the name of the Korban that he designated it), he fulfilled his Neder; but if it is Shechted 'she'Lo li'Shemah' (in the name of a different kind of Korban) then it is brought as a Nedavah - and the owner is obligated to bring another one to fulfill his Neder.
Yerushalmi Rosh Hashanah, 1:1: To teach us that if one delays sacrificing a number of Nedarim or a number of Nedavos, one transgresses 'Bal Te'acher ' on each animal. 1
See Torah Temimah, note 130.
Since the entire second half of the Pasuk - from "Ka'asher Nadarta" is superfluous, why does the Torah insert it?
Targum Yonasan and Rosh Hashanah, 6a: "Ka'asher Nadarta" - 'Zeh Neder"; "la'Hashem Elokecha" - 'Eilu Chata'os, va'Ashamos, Olos u'Shelamim'; "Nedavah" - 'ke'Mashma'ah': "asher Dibarta" - 'Eilu Kodshei Bedek ha'Bayis'; "be'Ficha" - Zu Tzedakah', 1 all of which are subject to Bal Te'acher.
See Torah Temimah, note 128. This teaches us that Tzedakah is subject to Bal Te'achar, though the Shi'ur differs from that of Korbanos.