Question: Someone who has a dream that it is Yom Kippur and he ate...

...And he was very upset in his dream, and his distress caused him to wake, and when he awoke and realized it was a dream he was very happy. And he asks what he should do about what he saw in his dream. He also says that one time he had a dream on a weeknight that it was Shabbat and he desecrated Shabbat by doing some forbidden from of work. Regarding this he also asks what he should do and if it requires atonement or not.

One who vows in their dream, it is meaningless and they don't need it to be annulled. However, there are those who say that it has to be annulled by ten literate judges (RAMA: And they find a point of regret, as if they had vowed awake.) And this [second] opinion should be heeded. RAMA: However, if it is difficult to find ten literate judges, one can then do it with three, as usual.

§ Rav Yosef said: One who was ostracized in a dream requires ten people to dissolve the ostracism for him.

Rav Aḥa said to Rav Ashi: If he was excommunicated and the excommunication was dissolved for him in his dream, what is the halakha? Rav Ashi said to him: Just as it is impossible for the grain to grow without straw, so too, it is impossible to dream without idle matter.

Regarding one who makes a vow or an oath in a dream. you asked if the require annulment , like one who is banned in a dream. Know that no action is required, because even someone who makes an oath while awake, but the mouth and heart are not in agreement [is exempt], how much more so in the case of a dream in which there is no mouth or heart at all. And this is not similar to one who was banned in a dream (Nedarim 8a) because that is a bad sign, that the person is being pushed away by heavenly force and needs to become close [again]....

Since the sages say "there is no dream that does not contain meaningless things" (Nedarim 8a), we find that each dream contains some truth and some meaningless things. Therefore, in this case, we see that the location and the amount of the money was true, but the concept of it being Maasar was not proven, certainly we ascribe the "truth" element of the dream to the location and amount, because it is impossible that these are meaningless because they have already been proven to be true. Therefore, we are forced to assign the "meaningless" portion of the dream to the part where he said that it was Maasar.

... In a case where he saw that they released him from the ban, if so, the vision of being released proves the truthfulness in the banning. Since he saw that they released him from the ban, how could we say that the banning is the falseness of the dream? One is forced to to ascribe the truth of the dream to the vision of being banned, and the falseness to the vision of being released. And that is why, in such a case, a person needs to be released [in real life].

Regarding someone who dreamt that he vowed publicly that he would not eat cooked Matzah this Pesach, if there is a way for him to be released from this, as in the case of one who made a vow in a dream (Shulchan Aruch, Yoreh De'ah 210:2), or since [the vow was made] with the consent of the public, perhaps there is no way to annul it... He is also in doubt as to whether [the vow in the dream] applies specifically to this Pesach, or perhaps we would say "there is not dream that does not contain meaningless things," and hhe would be forbidden [from eating cooked matzah] on every Pesach forever, like we say in the case of one who was banned and released in a dream, and we are concerned that the annulment was the meaningless part of the dream.

It is a meaningless thing to say that this part of the dream is a meaningless thing and it is forbidden for him on every Pesach. If so, then Pesach is a meaningless thing and it should be forbidden every day for him to eat cooked matzah. Also, "cooked" is a meaningless thing and all matzah should be forbidden to him. Therefore we must differentiate and create parameters: Specifically elements which stand on their own and do not depend upon one another, these are the things about which we say that one of them is insignificant. "Shall I, your mother and your brothers come and prostrate themselves on the ground to you?" (Bereishis 37:10) "Your mother has already died!" (Rashi on Bereishis 37:10). About this our sages said "there is no dream that does not contain meaningless things." Because only the sun and the 11 stars were [a vision] from the heavens, and the faculty of imagination created an extra, meaningless thing and added the moon. But we do not say that "bowed to me" is meaningless because bowing requires explanation: to whom were they bowing? The answer is "to me", and so this cannot be a meaningless addition. But the moon is a separate concept, because the sun and 11 stars do not require the presence of the moon. Therefore, we can say that this is the meaningless part of the dream. So too, one who is banned in a dream and is then released, because the banning does not logically demand the annulment that occured afterward, in which case we err toward assuming that the annulment is an extra part that came from his imagination and not rom the heavens.

Our fire is one-sixtieth of the fire of Gehenna; honey is one-sixtieth of manna; Shabbat is one-sixtieth of the World-to-Come; sleep is one-sixtieth of death; and a dream is one-sixtieth of prophecy.

A dream which comes from and angel is one sixtieth of prophecy. A drean which comes from a gremlin, this is meaningless, from the realm of death. And it is straw, as has been established, Just as it is impossible to have grain without straw, so too, it is impossible to dream without idle matter.

This is the nature of those dreams which prove true, and also of prophecy, the difference being one of quantity, not of quality. Thus our Sages say, that dream is the sixtieth part of prophecy: and no such comparison could be made between two things of different kinds, for we cannot say the perfection of man is so many times the perfection of a horse.

What is shown to man in a dream is like a person who who first arrives among a people who do not understand his language. And if they speak to him, he does not understand. So they hint to him with gestures , like those who hint to a deaf person.