What are "Badecha"?
Rashi: What you invent from your heart.
Devar Eliyahu: They are liars.
Malbim: Your high thoughts.
What are "Mesim"?
Rashi: They are people. Metzudas Tziyon - this is like "Mesei Mispar."
Malbim: They were weak people, who are not experienced in deep investigations.
What is the meaning of "Badecha Mesim Yacharishu"?
Devar Eliyahu: Liars, people rebuke them and say 'that is Sheker'! One who disgraces people, everyone disgraces him. Everyone is silent to your Sheker, and no one disgraces you for disgracing others! He mentioned the four Aveiros that come from speech, corresponding to the four groups that do not see the Shechinah. (a) Speaking at length - he spoke Leshon ha'Ra about Hashem! (b) Ish Sefasayim is a flatterer. He speaks only from the lips and externally. He wants to deceive people and be a Tzadik in their eyes, but in the end, [his true nature] will be revealed. (c) Badecha are liars. (d) Va'Til'ag (he mocks others).
Malbim: Your high thoughts silence simple people. They do not find an answer.
Why did he add "va'Til'ag v'Ein Machlim"?
Malbim: You disgrace simple people, who do not [know how to] disgrace you.
