What is the meaning of "Tafash ka'Chelev Libam"?
Radak: Their heart became fat, so they cannot understand Your Torah. Tafash is the Targum of "Hashmen Lev ha'Am ha'Zeh" (Yeshayah 6:10).
Malbim: Their heart became fat like lard. They go after lust of eating, and annul Mitzvos amidst lust. This makes their folly increase.
Why does it say "Torasecha Sha'ashati"?
Radak: This is like b'Sorasecha. Also "ha'Nimtza Veis Hashem" (Melachim II, 12:11, is like b'Veis).
Malbim: This is opposite those who follow lust of eating, and increase folly. Torah is my delight; it makes the heart astute to understand and weakens lust. It is called Toshiyah, because it weakens the power of the body and its lusts.
