Why did David compose this Mizmor?
Radak: It is like the previous Mizmor. David asks Hashem to silence him from worldly engagements and leave him to engage in needs of the Nefesh, i.e. Avodas Hashem.
Malbim: It is against evildoers whose mouths are unlike their hearts. They seem to be in counsel with (to help) him, and in secret they dug evil against him. They were trapped and fell in their hands' work. Hashem guarded David and Yisrael from death. It is not clear if this is when Zifim plotted evil against him, or Anshei Ke'ilah, or other haters, e.g. Sheva ben Bochri.
What is the meaning of "Al Techerash Mimeni"?
Radak: Do not be silent from hearing my request. Techerash is to be like a Cheresh (deaf-mute) - not to hear or answer my Tefilah.
Malbim: It is hard to beware of a hidden enemy. Only Hashem knows hidden thoughts. He can save from those who covertly plot evil. Therefore, do not be silent from me!
What is the meaning of "Techesheh"?
Radak: It is to be quiet, like "Es Lachashos" (Koheles 3:7).
What is the meaning of "Nimshalti Im Yordei Vor"?
Radak: I will be like Resha'im who descend to Gehinom. Their Nefesh perished when they die.
Malbim: [If You will be silent from me, and not inform me of those who covertly plot against me], I will be like those who descend to the pit (grave).
