TT #19 · Parashas Vayeitzei · Passuk 28:20
And Yaakov vowed a vow, saying, “If God will be with me and will guard me on this way that I am going, and will give me bread to eat and clothing to wear,
Torah Temimah points to classical sources on neder (Nedarim / midrash).
TT lemma: וידר יעקב נדר.
English: Chazal said: Our father Yaakov was the first who made a vow, and from him Yisrael learned to vow in a time of distress.
Derash on the verse (midrashic) — not a formal named middah of the 13. Yaakov’s vow is taken as the original model for later Jewish practice.
Yaakov originated the practice of making a vow in a time of need; later generations follow his example.