Gemara

(Abaye): Tachas connotes both Hatpasah (making something Kodesh through Temurah) and Chilul (redemption);

Regarding Kodshei Mizbe'ach, which make Temurah, surely he means Hatpasah;

Regarding Bedek ha'Bayis, which do not make Temurah, surely he means Chilul.

27b (Mishnah): If one said "this is Tachas Olah" or "Tachas Chatas" (and no Olah or Chatas was present), nothing takes effect;

(Rav Yehudah): Our Mishnah is unlike R. Meir, who says that a person does not say vain words.

Erchin 5a (Beraisa - R. Meir): If one vows to give the Erech of a baby less than a month old, he gives the Damim;

Chachamim say, the vow is void.

R. Meir holds that a person does not say vain words. He knows that Erchin do not apply to a baby before one month. Surely he meant to give the value.

Chachamim hold that people sometimes say things that have no effect.

Bava Basra 133a: If a Shechiv Mera wrote all his property to Ploni, if Ploni could inherit him, he receives it for an inheritance. If not, it is a gift.

174a (Rav Huna): If Levi told Reuven 'give to Shimon and I will be a Kablan', 'give to him and I will pay', 'give to him and I am liable'; or 'give to him and I will give', he becomes a Kablan.

(Rav Chisda): In all of Rav Huna's cases he becomes a Kablan, except for 'lend to him and I will be an Arev'.

(Rava): In all of Rav Huna's cases he becomes an Arev, except for 'give to him and I will give'.

Kidushin 8a (Rava): If one said 'be Mekudeshes to me for a Maneh', and he gave her a security, she is not Mekudeshes;

Since the Maneh is not here, the security does not take effect.

Rav Huna's children agreed to buy a slave for small coins. They did not have small coins with them. They left a piece of precious metal for a security. The value of the slave increased (and the seller wanted to retract).

R. Ami: The coins were never given, so the security has no effect.

Rishonim

Rashi (27a DH v'Im): 'Ta'amod' connotes Chilul (but 'Tachteha' connotes Temurah). Therefore, the Torah left it to Chachamim, who know when 'Tachas' connotes Temurah and when it connotes Chilul.

Hagahos ha'Gra (3): I cannot understand this. It should say 'presumably, a man intends for an expression that works.'

Rambam (Hilchos Mechirah 22:8): If one gave to Ploni a gift of land, and 100 Dinarim along with it, if the money was in his Reshus at the time, Ploni acquires also the money. If not, he need not give until Ploni can prove that he had Dinarim at the time.

Rambam (Hilchos Nedarim 12:10): If a married woman said 'my hands are Kodesh to their Maker', or vowed not to benefit from her Ma'aseh Yadayim (earnings), this does not forbid her earnings, for her husband has a lien on her earnings. Even though Hekdesh uproots liens, Chachamim strengthened a husband's lien so that she cannot uproot it. However, he must annul her vow, lest he divorce her and he will not be able to remarry her.

Sha'ar ha'Melech: The Tosfos Yom Tov asked that in Hilchos Erchin (6:28), the Rambam says that if one was Makdish his wife's Ma'aseh Yadayim, her earnings are not Kodesh (for they are not yet in the world). We do not say that since he mentioned her hands, it is as if he said 'your hands are Kodesh.' (When she says this, why does it take effect after divorce, and it would take effect immediately, if not for an enactment?) The Nesivos ha'Mishpat answered that since she can say 'do not feed me (and I will keep my earnings)', his words were l'Vatalah. Since she can say this, we explain her words as if she was Makdish her hands, because a person does not say vain words. The Rambam (Hilchos Erchin 1:3) rules like Chachamim, who say that a person says vain words! I answer that the Rambam holds that the Ritva (below), that Chachamim agree that we explain a person's words in a way that they take effect, as long as we need not change them.

Ritva (Kesuvos 58b DH meha'Hi): Even though the Halachah does not follow R. Meir regarding one who pledged the Erech of a baby less than 30 days old, this is because we do not change his words from Erchin to Damim (value). Here, when he said that he is Makdish her Ma'aseh Yadayim, we can say that he means that he is Makdish them like Chachamim's law and Torah law. It is as if he explicitly said 'they are Kodesh to their Maker.'

Rashbam (133a DH b'Ha): If Ploni could inherit him, we must say that the giver intended for a gift. A person does not say vain words. He intended for a gift, and not for an inheritance.

Maharsham (3:109): This is like R. Meir. We hold like Rabanan, that a person says vain words! I answer according to the Ritva, that they argue only if we need to add to his words to fulfill them. If we can explain his words in a way that they take effect without adding, all agree that a person does not say vain words. The Sha'ar ha'Melech wants to say that the Rambam holds like this. The Beis Yosef (CM 253:5) explained the Maharik this way, regarding a gift in an expression that does not take effect. Due to the Chazakah that a person does not say vain words, we must say that he intended for a gift, just he was not precise. Surely, when we need not say that he did not express himself properly, all agree that a person does not say vain words! Gitin 32a says so about Bitul of a Get.

Hagahah (from the Maharsham's grandson): I say that Chachamim argue only about saying words l'Vatalah, but if he did an act through his words, Rabanan agree that a person does not say vain words. Here, a command was written through his words. Regarding making Temurah, the Gra explains that presumably, one intended for an expression that works.

Sefer ha'Itur (2 Kinyan 10b, brought in Teshuvos Maimoniyos Mishpatim 67): A Teshuvah of the Rif says that if one said 'I gave this many gold coins with a Kinyan, and wrote a lien on my property to collect it' it is void, for coins are not acquired through Chalipin. We learn from Kidushin 8b. If no money was given, there was no security. The Ri mi'Gash derived that if one partially admitted to a claim and gave a security, this is not like Heilach (as if he gave it). Since no money was given, there was no security. I disagree. A document is like Heilach, and all the more so a security! Money or Shavah Kesef is needed to acquire a women or slave, but if one promised a gift and gave a security, the recipient may keep it until the gift is given. Since money need not be given, we do not say that since it was not given, the security is invalid. Also, presumably the Gemara discusses one who did not give the security until after (he discussed) buying the slave. If the security was given at the time of the sale, it is valid. The same applies to Kidushin. Therefore, if one said 'I put a lien on all my property until I give to you this amount', even though it is not in his hand, he acquires, whether this was a sale or gift. Anything that one stipulates about and is Meshabed his property for it through a Kinyan, the Kinyan helps. We find that a Shomer can stipulate to be obligated more than the Torah specified (Bava Metzi'a 94a). This is only when one was Makneh something that he did not have at the time. A Kinyan not to retract is Kinyan Devarim (which has no effect), and it does not take effect. Similarly, one who says 'I will do so and so or give to you so and so', this is Kinyan Devarim.

Poskim

Shulchan Aruch (CM 60:6): If Shimon wrote in a document 'I gave to Reuven 100 gold coins to collect from my property', if people do not use such coins for buying and selling, they are acquired through Chalipin, as long as they were in Shimon's Reshus at the time of the Kinyan. If this is not known, Reuven must bring a proof.

Beis Yosef (DH Reuven): Ba'al ha'Itur brings like this from Teshuvas ha'Rif; Ba'al ha'Itur brought proofs against it. Also Sefer ha'Terumos brought this from the Rif, and the Ra'avad's comments. The Ra'avad concluded 'I am not worthy to refute the Rif, but the judge himself can decide to be concerned (for my opinion). Since the Rif and Rambam agree, we rule like them.

Shach (29): I see no proof that the Rambam holds like the Rif. The Rambam said only that the property must be in his Reshus. Perhaps he agrees that 'I gave' is in a way that helps!

Rema: Shimon is believed to say 'I gave them to you', Migo (since) he could have said that they were not in his Reshus.

Beis Yosef (DH Kasuv): Sefer ha'Terumah brings from Teshuvas ha'Rif that we do not follow estimation, for some rich people do not have gold coins. The Rashba (2:194) said that the Teshuvah is not so clear. It seems that Ba'al ha'Itur did not agree.

Beis Yosef (DH u'Mah she'Chasav Rabeinu va'Adoni): The Rosh (Kesuvos 5:1) says that one can obligate himself something that he was not obligated. The Tur says that the Rif disagrees. I say that the Rif agrees. The Rif said only that if one admitted that he gave, and it was not in his possession, it is not a gift. The Rosh (Teshuvah 36:8) agrees.

Rema: This is the Rif's opinion. Many disagree, and hold that if one says 'I gave', a litigant's admission is like 100 witnesses. We are not particular about how he gave. Surely he gave in a way that works.

Gra (38): Many disagree due to Odisa (Bava Basra 149a - an admission is binding), even if we know that he did not owe.

Rema (129:18): If a document says 'Ploni is a Kablan', he is an Arev Kablan, for surely he said words that work.

SMA (40): This is unlike Sefer ha'Terumah (35:1:40), who says that the bearer of a document has the lower hand, for perhaps he said 'lend to him and I am a Kablan', which is only an expression of Arvus.

Shach (37): Maharshdam (9) rules like Sefer ha'Terumah and Ba'al ha'Itur, that he is only an Arev.

Gra (11): See the Rema above (60:6).