Why does it say "Bi Nishbati"?
Pirkei d'R. Eliezer (45): When Hashem asked Moshe to go to Pharaoh, Moshe asked Him to swear that He will do all that Moshe says. If not, Pharaoh will kill him! Hashem swore, except for two things - entering Eretz Yisrael, and the day of death.
Radak: The Shevu'ah is a decree that will not be retracted. This will be in the end of days, when all ends of the land will turn to Me.
Malbim: I swore in My great name; I will not retract.
What Tzedakah came from Hashem's mouth?
Kalah Rabasi (3:1): After a person dies, his mouth testifies about everything that he did in this world, and Hashem signs. Therefore, one must look at his end!
Rashi: He will accept allw ho repent to Him; "every knee will bow to Me", like it says "Ki Az Ehpoch El Amim [Safah Berurah Likro Kulam b'Shem Hashem Le'avdo Shechem Echad]" (Tzefanyah 3:9).
Radak: What leaves My mouth is b'Tzedek - it will not be retracted.
Malbim: Even without the Shevu'ah, any matter of Tzedakah and Chesed that I promised, I never deviate (unlike what He says to do evil, which can be retracted if they repent).
What is the significance of every knee bowing to Him?
Malbim: I will accept all nations under the true Emunah, until every knee will bow to Me.
What is the significance of "Tishava Kol Lashon"?
Radak: This is like "uvi'Shmo Tishave'a" (Devarim 10:20). They will not mention other gods. They will bow only in front of Kel, pray [only] to Him and swear Emes in His name.
Malbim: They will accept with a Shevu'ah to serve only Me, and not another god.
