Why does it say "v'Nishbata Chai Hashem be'Emes"?
Rashi: When you swear in My name, swear truthfully - not like it says about you "v'Im Chai Hashem Yomeru Lachen la'Sheker Yishav'u" (5:2).
Malbim: You say that you despair. I counsel you to swear in My name to strengthen the matter, that from now you will choose Emes, Mishpat and Tzedakah - three things on which the world stands.
Why does it say "be'Emes b'Mishpat uvi'Tzedakah"?
Radak citing his father: "Be'Emes" - when you know that it is true. "B'Mishpat" - when the law requires you to swear. "Uvi'Tzedakah" - if you recognize that the Mishpat (verdict) is not bi'Tzedakah (correct), do not accept the Shevu'ah.
Radak citing Targum Yonasan: If you swear in My name, sustain Hashem in truth, in judgment and in merit. I.e. if you must swear, swear truthfully.
Radak: Perhaps this is like "uvi'Shmo Tishave'a" (Devarim 6:13). Swearing in the name of Hashem is honor for one who fears Him and serves Him with a full heart. When there is occasion to swear, it is a Mitzvah. When he swears, he is like one who praises Him and aggrandizes Him, like it is the way of the world to swear in what one loves more, e.g. his Nefesh or his head. The Nevi'im always used to swear. Not everyone is proper to swear, even truthfully - only Yir'ei Hashem and those who love Him. "You will fear Hashem, and serve Him, cling to Him and swear in His Name" (Devarim 10:20). Chazal (Bamidbar Rabah 22:1) said that if you have all of these Midos, it is proper for you to swear in His name, and if not, you may not.
Malbim: Emes is belief in matters of investigation, e.g. knowing the unity of Hashgachah, reward, and other true fundamental principles. Mishpat encompasses actions Bein Adam l'Chavero, and Tzedakah is Bein Adam l'Makom. They correspond to Torah, Avodah and Gemilus Chasadim (Avos 1:2).
Why does it say "v'Hisbarchu Vo Goyim"?
Rashi: If you do so, the nations will bless via you. Every Goy will say to his son 'be like Ploni the Yisrael!' Radak - this is like "v'Hisbarachu b'Zar'acha Kol Goyei ha'Aretz" (Bereishis 22:18). Even though v'Hisbarchu is in second person and Vo is in third person, many verses are like this.
Radak: There will come a time when even other Goyim will bless Him and praise Him, and not their idols.
Malbim: Brachah is the influence that one who is blessed and believes in Him receives. It is the opposite of Bushah.
What is "Yis'halelu"?
Rashi #1 They will tell your praises.
Rashi #2: One who can cling to you will boast about it.
Malbim: Hilul is boasting to all about the influence that one [who believes in Him] receives. It is the opposite of Kelimah.
