Rosh Hashanah, 5b: We learn via a Gezeirah Shavah "Neder" "Neder" from Pasuk 24, that, just as there, the Pasuk incorporates Nedavah, so too, here.

Rosh Hashanah, 5b: To incorporate Hekdesh Damim, Arachin, Charamos and Hekdeshos in the prohibition. ¹

Yerushalmi Rosh Hashanah, 1:1: To incorporate Hekdesh Bedek ha'Bayis in the prohibition. ²

Based on the Seforno: Because, jut as one is obligated to fulfill one's promise to pay a Nochri Ribis, ¹ so too, must one who declares a Neder keep his word at all costs ? and to do so without delay.

Rashi and Targum Yonasan: Three Yamim-Tovim (Pesach, Shavu'os and Sukos, in whichever order they occur following the Neder - Rosh Hashanah, 4a, according to the Chachamim). ¹

Rosh Hashanah 4a (according to R. Shimon): It is three Yamim-Tovim, starting from Pesach.

Seforno: It implies that if you don't pay what you promised on time, Hashem will claim it from you against your will.

Oznayim la'Torah: The Torah writes the double Lashon "Darosh Yidr'shenu Hashem Elokecha me'Imach" - like we find by Ya'akov Avinu, whom Hashem reminded twice to go and fulfil his Neder. ¹

Rosh Hashanah, 5b: It comes to incorporate Leket, Shikchah and Pe'ah in the Din of 'Bal Te'acher'. ¹

Rosh Hashanah, 6b: It implies "me'Imach" 've'Lo mi'Yorshecha', to exempt heirs from 'Bal Te'acher' on Korbanos that they inherit from their father. ²

Seforno: It implies that even if one ultimately fulfills one's Neder against one's will, ¹ he will still be punished for delaying it.

Targum Yonasan Rosh Hashanah, 5b): "b'cha Chet", 've'Lo be'Korbancha Chet' - The Korban does not become Pasul even after three Yamim-Tovim have passed, because 'the moment one designates it, it enters the storehouse of Hakadosh-Baruch-Hu'. ¹

Rosh Hashanah, 6a: "b'cha Chet", 've'Lo be'Isht'cha Chet' - The sin of Bal Te'acher will not cause the death of one's wife. ²