So is the man that deceiveth {i} his neighbour, and saith, Am not I in sport?

(i) Who disguises himself to be that which he is not.

Matthew Henry's Concise Commentary

26:2. He that is cursed without cause, the curse shall do him no more harm than the bird that flies over his head. 3. Every creature must be dealt with according to its nature, but careless and profligate sinners never will be ruled by reason and persuasion. Man indeed is born like the wild ass's colt; but some, by the grace of God, are changed. 4,5. We are to fit our remarks to the man, and address them to his conscience, so as may best end the debate. 6-9. Fools are not fit to be trusted, nor to have any honour. Wise sayings, as a foolish man delivers and applies them, lose their usefulness. 10. This verse may either declare how the Lord, the Creator of all men, will deal with sinners according to their guilt, or, how the powerful among men should disgrace and punish the wicked. 11. The dog is a loathsome emblem of those sinners who return to their vices, 2Pe 2:22. 12. We see many a one who has some little sense, but is proud of it. This describes those who think their spiritual state to be good, when really it is very bad. 13. The slothful man hates every thing that requires care and labour. But it is foolish to frighten ourselves from real duties by fancied difficulties. This may be applied to a man slothful in the duties of religion. 14. Having seen the slothful man in fear of his work, here we find him in love with his ease. Bodily ease is the sad occasion of many spiritual diseases. He does not care to get forward with his business. Slothful professors turn thus. The world and the flesh are hinges on which they are hung; and though they move in a course of outward services, yet they are not the nearer to heaven. 15. The sluggard is now out of his bed, but he might have lain there, for any thing he is likely to bring to pass in his work. It is common for men who will not do their duty, to pretend they cannot. Those that are slothful in religion, will not be at the pains to feed their souls with the bread of life, nor to fetch in promised blessings by prayer. 16. He that takes pains in religion, knows he is working for a good Master, and that his labour shall not be in vain. 17. To make ourselves busy in other men's matters, is to thrust ourselves into temptation. 18,19. He that sins in jest, must repent in earnest, or his sin will be his ruin. 20-22. Contention heats the spirit, and puts families and societies into a flame. And that fire is commonly kindled and kept burning by whisperers and backbiters. 23. A wicked heart disguising itself, is like a potsherd covered with the dross of silver.

Matthew Henry's Whole Bible Commentary

Verses 18-19

See here, 1. How mischievous those are that make no scruple of deceiving their neighbours; they are as madmen that cast firebrands, arrows, and death, so much hurt may they do by their deceits. They value themselves upon it as polite cunning men, but really they are as madmen. There is not a greater madness in the world than a wilful sin. It is not only the passionate furious man, but the malicious deceitful man, that is a madman; he does in effect cast fire-brands, arrows, and death; he does more mischief than he can imagine. Fraud and falsehood burn like fire-brands, kill, even at a distance, like arrows. 2. See how frivolous the excuse is which men commonly make for the mischief they do, that they did it in a jest; with this they think to turn it off when they are reproved for it, Am not I in sport? But it will prove dangerous playing with fire and jesting with edge-tools. Not that those are to be commended who are captious, and can take no jest (those that themselves are wise must suffer fools, 2 Co. 11:19, 20), but those are certainly to be condemned who are any way abusive to their neighbours, impose upon their credulity, cheat them in their bargains with them, tell lies to them or tell lies of them, give them ill language, or sully their reputation, and then think to excuse it by saying that they did but jest. Am not I in sport? He that sins in just must repent in earnest, or his sin will be his ruin. Truth is too valuable a thing to be sold for a jest, and so is the reputation of our neighbour. By lying and slandering in jest men learn themselves, and teach others, to lie and slander in earnest; and a false report, raised in mirth, may be spread in malice; besides, if a man may tell a lie to make himself merry, why not to make himself rich, and so truth quite perishes, and men teach their tongues to tell lies, Jer. 9:5. If men would consider that a lie comes from the devil, and brings to hell-fire, surely that would spoil the sport of it; it is casting arrows and death to themselves.