What is the meaning of "Melitzei"?
'Rashi': They are Sheluchim. This is like "ha'Melitz Beinosam" (Bereishis 42:23), because the Shali'ach is Melitz (advocates, or translates) between the sender and the one to whom he is sent.
Is "Melitzei" Samuch?
Radak: Yes ? it is Samuch to Sarei, which is Samuch to Bavel. We find like this ? "Naharei Nachalei Devash v'Chem'ah" (Iyov 2:17), "Mivchar v'Tov Levanon" (Yechezkel 31:16).
Is this connected to the previous verse?
'Rashi': Yes. After all the success that Hashem gave to him, Hashem abandoned him to test what is in his heart, via the Sheluchim of Bavel that were sent to him. The end of our verse explains the beginning. Malbim ? he failed the test, and aggrandized himself in front of the Sheluchim, like I explained in Yeshayah (refer to Yeshayah 39:2:1:1).
Why does it say "Lada'as Kol bi'Lvavo"?
Radak: This is Kol Asher bi'Lvavo. He rejoiced over them, and showed all his wealth and became haughty; Hashem considered this a sin. "Lada'as" is so other people will know.
