So is the man that deceiveth his neighbour, and saith, Am not I in sport?
Jesting is not convenient - appropriate, proper, or suitable. It causes confusion, pain, and trouble. It destroys confidence and security. This is especially true when you jest with those who trust you. The man who deceives his neighbor either for advantage or foolish joking is like a mad man throwing firebrands, arrows, and death (Pr 26:18). Truth is a wonderful thing, and it should not be mocked. Your neighbor trusts you - be worthy of it.
This verse is the second half of a proverb against jesting (Pr 26:18-19). The analogy and simile require the first half of the warning to make sense - "As a mad man who casteth firebrands, arrows, and death ... so is the man that deceiveth his neighbour, and saith, Am not I in sport?" King Solomon had no use for profane individuals who play tricks on others for profit or pleasure and excuse their wickedness by calling it a game or a joke.
This foolish generation jests for entertainment! Prime time sitcoms are one continuous stream of deceptions and jests, at which a studio audience laughs on cue to sell the insanity to mindless and heartless viewers. It is hard to grasp Solomon's sober and severe warning, since modern man is numb to such foolishness and ignorant of sobriety. Reader, would your grandparents sit around and cackle with such profane hyenas every night?
Jesting is not convenient. It has no noble or useful purpose. It is contrary to nature and true religion. How can a man be esteemed, who takes serious matters of life and turns them into jokes and games? Lovemaking is a holy and noble pleasure for husbands and wives. But sitcoms and comedians depend heavily on innuendo about sexual wickedness and outright jests about body parts and activities. It is an accomplice to sexual sins!
What is the lesson? Deceiving those who trust you is a horrible crime. Neighbors, employers, and others trust your integrity. You are close enough to take advantage of them, so they must trust you to not use that nearness against them. It is your duty as a Christian to live honestly with all men, but especially those nearest to you.
Is there another lesson? God hates foolish talking and jesting! He will destroy the world for these heinous sins. He lists foolish talking and jesting with fornication, uncleanness, and covetousness, three abominable sins (Eph 5:3-7). And He describes foolish talking and jesting as He does sodomy - they are not convenient (Eph 5:4 cp Rom 1:28).
Is there another lesson? Covering and excusing sin by lightly claiming it was just a joke reveals a very profane character. Such persons have no conscience; they laugh at sin; they do not comprehend the pain their deception causes others. We oppose this folly by keeping and requiring a sober and serious approach to all relationships.
Is there another lesson? Only fools make a mock at sin (Pr 10:23; 14:9; 15:21). Sin is a horrible thing - it defies your Creator God, hurts your fellow man, is inconvenient for profitable relationships, and leads to eternal punishment. The blessed God once drowned the world because of sin, and He will burn the world up soon for the same reason. Only hopeless scorners laugh and jest about sin. Sin is to be avoided, hated, and repented of!
These wicked men, like an insane man hurling fire, arrows, and death, can show up even in Jesus Christ's churches - counting it a pleasure to riot and sporting themselves with their deceivings (II Pet 2:13). Beware of frivolity in the pulpit or church! Of all places on earth, gravity and sobriety should reign in the house of God (I Tim 3:2,4,8,11; Titus 1:8; 2:2,4,6,7). Lord, save your saints from such sins and sinners!