| Gill's Exposition of the Entire Bible 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.
Geneva Study BibleFor their heart studieth destruction, and their lips talk of mischief.
Wesley's Notes 24:2 Destruction - How they may oppress and destroy others.
Jamieson-Fausset-Brown Bible Commentary2. studieth-meditateth. talk . mischief-Their expressed purposes are to do evil.
Matthew Henry's Concise Commentary24:1,2 Envy not sinners. And let not a desire ever come into thy mind, Oh that I could shake off restraints! 3-6. Piety and prudence in outward affairs, both go together to complete a wise man. By knowledge the soul is filled with the graces and comforts of the spirit, those precious and pleasant riches. The spirit is strengthened for the spiritual work and the spiritual warfare, by true wisdom. 7-9. A weak man thinks wisdom is too high for him, therefore he will take no pains for it. It is bad to do evil, but worse to devise it. Even the first risings of sin in the heart are sin, and must be repented of. Those that strive to make others hateful, make themselves so. 10. Under troubles we are apt to despair of relief. But be of good courage, and God shall strengthen thy heart. 11,12. If a man know that his neighbour is in danger by any unjust proceeding, he is bound to do all in his power to deliver him. And what is it to suffer immortal souls to perish, when our persuasions and example may be the means of preventing it? 13,14. We are quickened to the study of wisdom by considering both the pleasure and the profit of it. All men relish things that are sweet to the palate; but many have no relish for the things that are sweet to the purified soul, and that make us wise unto salvation. 15,16. The sincere soul falls as a traveller may do, by stumbling at some stone in his path; but gets up, and goes on his way with more care and speed. This is rather to be understood of falls into affliction, than falls into actual sin.
Matthew Henry's Whole Bible CommentaryChapter 24 Verses 1-2 Here, 1. The caution given is much the same with that which we had before (ch. 23:17), not to envy sinners, not to think them happy, nor to whish ourselves in their condition, though they prosper ever so much in this world, and are ever so marry and ever so secure. "Let not such a thought ever come into thy mind, O that I could shake off the restraints of religion and conscience, and take as great a liberty to indulge the sensual appetite, as I see such and such do! No; desire not to be with them, to do as they do and fare as they fare, and to cast in thy lot among them." 2. Here is another reason given for this caution: "Be not envious against them, not only because their end will be had, but because their way is so, v. 2. Do not think with them, for their heart studies destruction to others, but it will prove destruction to themselves. Do not speak like them, for their lips talk of their mischief. All they say has an ill tendency, to dishonour God, reproach religion, or wrong their neighbour; but it will be mischief to themselves at last. It is therefore thy wisdom to have nothing to do with them. Nor hast thou any reason to look upon them with envy, but with pity rather, or a just indignation at their wicked practices." | 
