Why does the Torah see fit to add "Motzei Sefasecha Tishmor ve'Asisa "?
Rashi: To add an Asei to the Lo Sa'aseh. 1
Ramban (on 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 a Lo Sa'aseh from "Tishmor", and an Asei from "Motzei Sefasecha." 3
Yerushalmi Rosh Hashanah, 1:1: "ve'Asisa" also 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.
See Tosfos DH 'Zu'. This is because the Torah writes in Matos Bamidbar, 32:24 "ve'ha'Yotzei mi'Pichem Ta'asu". Gur Aryeh
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.
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, wy does the Torah insert it?
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.
