What is "v'Hagus Libi"?
Rashi: The thoughts of my heart.
The author comes to rebuke. How will his heart's thoughts help?
Malbim: Amidst the external words that my mouth says, deeper Binah (understanding) is contained. E.g. he will say that money and wealth are illusory acquisitions (verses 17-18) - this is from Chachmah. The explanation is from ways of understanding. Man must switch external Kinyanim for Kinyanim more intrinsic to himself. E.g. money for the sake of his body - the Nefesh is more intrinsic to a person than his body. The consequence is that one must switch bodily desires for happiness of the Nefesh. This is built on the foundation from Chachmah of the essence of the Nefesh, and that it is the person himself.
