Whom do they melt?
Rashi: Their colleagues.
Radak: People. This is only place in Tanach where this is a three letter root (and the middle letter (Yud) is not pronounced as a consonant), but we find this in the Gemara (Memikato - Kesuvos 77a), and we find it without the Yud - "Hamek Besaro... u'Leshono Timak b'Fihem" (Zecharyah 14:12), "v'Namak Kol Tzva ha'Shamayim" (Yeshayah 34:4).
Malbim: Refer to 73:8:3:3.
What do we learn "va'Ydabru v'Ra Oshek"?
Rashi: They oppress the poor.
Radak: They did not fear to discuss the oppression they do, and did not cover it up.
Malbim: Refer to 73:8:3:3.
What is the meaning of "mi'Marom Yedaberu"?
Rashi: This is like Pharaoh, Sancheriv and Nebuchadnetzar - "Mi Hashem Asher Eshma v'Kolo" (Shemos 5:2), "Mi b'Chol Elohei ha'Aratzos... [Ki Yatzil Hashem... mi'Yadi]", "E'eleh Al Bamasi Av [Adameh l'Elyon]" (Yeshayah 36:20, 14:14).
Radak: They say that there is nothing above them that will punish them (for their theft).
Malbim: The verse depicts that speech comes out of Shamayim. There they speak and decree about these Resha'im that it is proper that they melt, and die via a plague for their Oshek. They are not afraid of these decrees above!
