For their heart studieth destruction,.... To others; to good men, that separate from them, and reprove them, or are in their way; or any ways hinder them in the prosecution of their wicked designs; as Haman's heart studied the destruction of the Jews: or their hearts study to draw men into their destructive methods of living, and therefore should be shunned and avoided. Moreover, their hearts study destruction to themselves; they study what they shall eat and drink, which they pursue to intemperance; and how they shall compass their lewd designs, and which issue in their ruin; destruction and misery are in all the ways they devise and walk in;

and their lips talk of mischief; which they study in their hearts against others; as are their hearts, so are their lips; out of the abundance of the wickedness of their hearts their mouths speak mischievous things; and which, though they design for others, oftentimes fall upon themselves.

studieth--meditateth.

talk . . . mischief--Their expressed purposes are to do evil.