Having taught us the La'av of swearing falsely in the Aseres ha'Dibros, why does the Torah repeat it here?
Rashi (citing the Sifra) and Ramban (according to Kabalah): Because there, the Torah forbids swearing by the Name of Havayah; threfore here, "Lo Sishav'u vi'Shemi" 1 comes to include all Names of Hashem in the prohibition.
Seforno: Continuing with the sequence of Mitzvos discussed in this Parshah, 2 the Torah discusses someone who harms his fellow-Jew by not paying him what he owes him, 3 in addition to the Chilul Hashem that swearing falsely causes.
Hadar Zekenim: It is placed after Geneivah, to teach us that if one steals, in the end he will swear falsely. Theft can be returned, but Shevu'as Sheker cannot be fixed.
Shevu'os, 21a: Whereas the Pasuk here is talking about a Shevu'as Sheker - 'Achalti' ve'Lo Achalti', the Pasuk in the Aseres ha'Dibros is talking about a Shevu'as Shav 4 - falsifying known facts. 5
Ramban (Ibid.): "Lo Sishav'u vi'Shemi" refers to the Name of Havayah, "ve'Chilalta es Sheim Elokecha" comes to include all other Names of Hashem, which are all branches of 'Elokim'. In fact, the Torah uses virtually the same two phrases in the Aseres ha'Dibros - to include all Names of Hashem, only in the reverse order. See R. Chavel's footnotes.
Refer to19:11:1:1*.
Seforno: and it follows with a La'av against harming his self-esteem by cursing him.
What are the implications of "ve'Lo Sishav'u vi'Shemi la'Shaker" (See Torah Temimah)?
Yerushalmi Nedarim, 3:4: It implies that one may swear falsely to murderers and self-appointed tax-collectors. 1
Sifra: Having written in the Aseres ha'Dibros "Lo Sisa es Shem Hashem Elokecha ... ", "vi'Shemi" teaches us that the prohibition extends to any Name of Hashem by which one swears.
See Torah Temimah, note 64.
Why does the Torah insert the words "Ani Hashem" here?
Rashi: Refer to 19:10:5:1 and note.
Nachal Kedumim (citing the Zohar): When Hashem created the world, he engraved His name on a rock and put it over the T'hom. When people swear falsely, the letters fly off, the rock and the water below wants to flood the world. 1 "Ani Hashem" - Midas ha'Rachamim reinstates the Name like it was.
Sukah 53a-b: Similarly, when David was digging foundations for the Beis ha'Mikdash, water from the T'hom wanted to flood the world. He stopped it through via a piece of Cheres with Hashem's name on it,
Why is "Lo Sishav'u" written in the plural?
Moshav Zekenim (in Pasuk 9): To teach us that if Reuven claims money Shimon, who does not owe him anything and causes him to swear, he is included in the La'av.
Why does the Torah write "ve'Chilalta", and not 'Lo Sechalel'?
