13. Govern your TONGUE! More sin, it is probable, is committed, and more mischief done, by this small member—than in all other ways. The faculty of speech is one of our most useful endowments, but it is exceedingly liable to abuse. He who knows how to bridle his tongue is, therefore, in Scripture, denominated “a perfect man.” (James 3:2) Again, of him “who seems to be religious and bridles not his tongue”, (James 1:26) it is declared that “this man’s religion is vain”. The words which we utter are a fair index of the moral state of the mind. “By your words,” says our Lord, “shall you be justified, and by your words shall you be condemned.” (Matt 12:37) Not only are sins of the tongue more numerous than others, but some of them are the most heinous of which man can be guilty. That one sin which has no forgiveness, is a sin of the tongue.
Not only should all profaneness, obscenity, and falsehood be put far away, but you should continually endeavor to render your conversation useful. Be ever ready to communicate godly knowledge, to suggest profitable ideas, to recommend virtue and piety, to rebuke sin, and to give glory to God. Beware of evil-speaking. A habit of criticism is one of the worst which you can contract—and is always indicative of an envious and malignant heart. Instead of prostituting this active and useful member to the purposes of slander, employ it in defending the innocent and the injured.
Permit me to suggest the following brief rules for the government of the tongue.
Avoid loquacity. “When there are many words, sin is unavoidable, but the one who controls his lips is wise.” (Prov 10:19) If you have nothing to communicate which can be useful—then be silent.
Think before you speak. How many painful anxieties would be prevented by obeying this simple, common-sense precept.
Especially, be cautious about uttering anything in the form of a promise, without consideration. Be conscientiously regardful of truth, even in the smallest things—in all that you say.
Never speak what will be likely to excite bad feelings of any kind in the minds of others. Be ready on all suitable occasions to give utterance to good sentiments, especially such as may be useful to the young.
Listen respectfully to the opinions of others, but never fail to give your testimony, modestly but firmly, against error. “Let your speech be always with grace, seasoned with salt. Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.” (Col 4:6; Eph 4:29)
– Archibald Alexander; Counsels of the Aged to the Young (See here for more info)