Why does it say "Divrei Piv Aven u'Mirmah"?
Radak: If he speaks nicely with his mouth, it is deceit, for he plots evil in his heart.
Malbim: After bringing Pesha's claims, David says that (a) its proofs from investigation are fraud, and (b) its claims based on practical intellect are good in his eyes only because his heart is full of sin!
What is the meaning of "Chadal Lehaskil Leheitiv"?
Rashi: He prevented himself from being wise to improve his ways.
Radak: He ceased to take Musar to make his heart wise [to improve his ways].
Malbim: The investigative intellect erred (refer to 36:4:1:2) because it ceased to try to grow wise. Had it grown wise, it would have found the Emes! The practical intellect erred because it ceased to try to improve its ways. Had it done so, it would have sensed that Mitzvos are good and precious!
