וידר יעקב נדר לאמר אם יהיה אלקים עמדי ... וכל אשר תתן לי עשר אעשרנו לך
The word leimor, saying, is an implication to future generations, that they, too, shall vow in times of distress. Chazal (Midrash Rabbah, Bereishis 70) say, “Yaakov was the first to vow, thus all those who vow in the future should attach their vow to him.” Yaakov Avinu merited that all sincere vows be connected and attributed to his vow. He paved the way for people to vow to Hashem. Thus, when anyone commences a mitzvah, a project, an endeavor that will help others or increase service to Hashem, the merit all reverts to he who took the first plunge, who…