They conceive mischief, i.e. they devise and contrive injurious and pernicious enterprises against others. Vanity, or iniquity, or injury, or trouble; either,
1. To others; they execute what they had contrived. Or,
2. To themselves; the mischief they designed for others falleth upon their own heads, and they reap what they sowed. And their belly, i.e. their inward parts, their hearts and minds. See Poole on "Job 15:2". Prepareth deceit; either,
1. For others, whom they design to cheat; or,
2. For themselves, who whilst they seek to deceive others, shall find that they themselves are most deceived, as being deprived of all their desires and hopes wherewith they fed themselves, and cast into all those calamities which they thought to prevent by these artifices.