“Jacob took a vow, saying: If God will be with me, and He will keep me on this way that I go, and will give me bread to eat, and a garment to wear” (Genesis 28:20). “Jacob took a vow, saying: If God will be with me…and will give me bread to eat.” It is written: “Those uttered by my lips and spoken by my mouth when I was in distress” (Psalms 66:14) – Rabbi Yitzḥak HaBavli said: “And spoken by my mouth when I was in distress” – as he vowed to perform a mitzva in his time of distress.
What is “saying”? It is: Saying to the generations, so they would take vows in their time of distress. Jacob began with a vow first; therefore, anyone who takes a vow will ascribe the vow only to him. Rabbi Abbahu said: It is written: “Who took an oath to the Lord and took a vow to the Champion of Jacob” (Psalms 132:2) – to the Champion of Abraham or to the Champion of Isaac is not written here, but rather, “took a vow to the Champion of Jacob” – he ascribed the vow to the one who began with it first.