The Four Who Vowed - Jacob, Jephthah, Israel, and Hannah

It is written, "And Jacob vowed a vow, saying" (Genesis 28:20). Rabbi Yitzchak the Babylonian said: Anyone who makes a vow performs a commandment. What is "saying"? "Saying" to the generations, that they should make vows in their time of distress. Therefore, whoever makes a vow makes his vow depend on none but Him. Rabbi Abbahu said: It is written, "How he swore unto the LORD, and vowed unto the Mighty One of Jacob" (Psalms 132:2). It does not say here "to the Mighty One of Israel," but rather "to the Mighty One of Jacob." And Rabbi Chuna in the name of Rabbi Idi: It is written, "Then the people rejoiced, for that they offered willingly, because with perfect heart they offered willingly unto the LORD" and so forth (1 Chronicles 29:9) — because they were occupied with the commandment of freewill offering and it succeeded in their hands, they rejoiced. What is written after it? "Wherefore David blessed the LORD before all the congregation; and David said, Blessed be Thou, LORD, [God of Israel our father]" (1 Chronicles 29:10). "God of Abraham and Isaac" is not written, but rather "God of Israel our father." Rabbi Yudan said: Even from its place it lacks nothing. "And Israel vowed" — it does not say here vayidru [in the plural], but rather vayidar Yisrael, "And Israel vowed" [in the singular] (Numbers 21:2) — Israel the Elder. Four made vows. Two vowed and lost, and two vowed and profited. Jacob and Jephthah vowed and lost; Israel and Hannah vowed and profited.