No Promises

Yet the phrase carries genuine halachic weight, especially in the context of tzedakah. The halachic parameters for what constitutes a vow are broader when it comes to pledges involving mitzvos. As a result, when someone makes a Mi Sheberach and pledges to give charity, it is customary—and highly advisable—to say bli neder, just in case the promise is forgotten or unfulfilled.

But perhaps bli neder is more halachically relevant than it first appears.

The Gemara teaches that simply saying, “I will do something” or “I will not do something” can constitute a vow. This is derived from a verse in Yeshaya (54:9) where it states that Hashem swore never again to bring a great flood upon the earth. Nowhere in the Torah is this oath explicitly stated. It must be that when Hashem said that He would not bring a flood, it is considered an oath.

This interpretation seems like a tremendous chumra. Rava clarifies that the Gemara refers to someone who says twice, “I will do” or “I will not do” something. The repetition elevates the commitment to the status of a vow. Rava states similarly that Hashem stated twice that He would not bring a great flood again. Since Hashem repeated it twice, it is considered a vow. Still, the Rashba places a significant limitation on this principle: it only applies if the person intended to make a vow. If someone simply says, “I will go to the store,” and then repeats it, it’s not a vow unless he consciously meant it as one. The Gemara is merely providing a formula for a valid vow if there was an intent to make one.

Tosafos, however, takes a different approach and outright disagrees. According to Tosafos, the Gemara isn’t discussing a legally binding oath at all. Instead, it serves as a moral or spiritual warning: when one repeats a statement of intent, it carries extra weight. Tosafos comments: “Ketzas yesh onesh b’davar”—there may be some punishment if the commitment is not upheld. Though not a formal neder, it is still more serious than casual speech. Thus, according to Tosafos, if someone says, “I’ll buy lunch today” and then repeats it, the statement has now risen above casual talk, even without intent to vow. In such a case, it would be appropriate to say “bli neder,” to make it clear that the commitment isn’t intended as more than one’s word.

Nonetheless, as a matter of practical halacha, the Shulchan Aruch (Yoreh De’ah 237:5) does not follow Tosafos. Instead, it rules like the Rashba: without intention to vow, there is no vow.

The Shulchan Aruch adds one further limitation based on the view of the Rosh. For a repeated statement to qualify as an oath, the two declarations must be consecutive. For example:

“I will go to the store. I will go to the store.”

However, in the following exchange, the statements are not consecutive and thus do not form a vow:

“I will go to the store.”

“Really?”

“Yes, I will go to the store.”

In any case, the Shulchan Aruch maintains that intent remains the critical factor. Without it, there is no halachic consequence.

Based on the above Gemara, the Vilna Gaon offers a striking interpretation of a verse in Malachi (3:6):

“Ki ani Hashem lo shanisi, v’atem Bnei Yaakov lo kilisem, for I, Hashem, have not changed; and you, the children of Yaakov, have not been destroyed.”

The Vilna Gaon reads “lo shanisi” alternatively as: “I repeated the word ‘lo’ (no).” In other words, Hashem is saying, “I made a vow not to destroy the Jewish people by repeating the word ‘lo.’” Where is this found?

In Vayikra 26:44 (Parashat Bechukosai), Hashem promises regarding the Jewish people in exile: “V’af gam zos b’heyosam b’eretz oyveihem, lo m’astim v’lo g’altim l’chalosam, l’hafeir brisi itam, yet even so, when they are in the land of their enemies, I have not rejected them, nor have I abhorred them to destroy them and annul My covenant with them.”

According to the Vilna Gaon, the repetition of “lo” (I have not) constitutes a divine oath.

He further explains that this idea ties back to the original verse in Yeshaya (54:9):

“Just as I swore never again to let the waters of Noach flood the earth, so have I sworn not to be angry with you or rebuke you.”

Why does the verse link the Flood with Hashem’s promise to Klal Yisrael? Because just as we learn from the repetition in reference to the Flood that saying something twice constitutes an oath, so, too, we learn that Hashem’s double expression in Bechukosai likewise forms an oath – guaranteeing that He will never utterly abandon His people.