There are repeated warnings against evil-speaking (as in Ps 34:13; Prov 15:28; Eph 4:31; Col 3:8; James 4:11; 1 Peter 3:10), which is the cause of so much strife between man and man (Prov 16:27-30), and which recoils on the speaker himself to his destruction (Ps 101:5; 140:11). Especially is false witness, which is "slander carried into a court of justice," to be condemned and punished (Ex 20:16; Deut 19:16-21; compare Prov 12:17; 14:5,25; 19:5; 21:28; 24:28). Special cases of slander more than usually mean are when a wife's chastity is falsely impeached by her husband (Deut 22:13-19), and when one slanders a servant to his master (Prov 30:10). Even a land may be slandered as well as persons (Num 14:36). Slanderers and backbiters are mentioned in some of Paul's darkest catalogues of evildoers (Rom 1:29-30; 2 Cor 12:20; 2 Tim 3:3). To refrain from slander is an important qualification for citizenship in theocracy (Ps 15:1,3; 24:3-4) and for a place in the Christian church (1 Tim 3:11; Titus 2:3). Jesus Himself was the victim of slanders (Matt 11:19) and of false testimony (Matt 27:63). The apostles, too, came in for a full share of it (e.g. Acts 24:5 f; 28:22; 6:8). In the case of Paul, even his central doctrine of justification was "slanderously reported" as if it encouraged immorality (Rom 3:8). The devil ( = "the calumniator") is represented as the great accuser of God's people (Rev 12:10), the slanderer paragraph excellence (compare Job 1:9-11; Zech 3:1). See also CRIMES; PUNISHMENTS.

(from International Standard Bible Encyclopaedia, Electronic Database Copyright (c)1996 by Biblesoft)

There is nothing more dear and valuable to men than their reputation or good name. Men, for the most part are always careful to preserve their good name so you would think that they would think twice before taking it wrongfully from someone else. We are only as good as the reputation that precedes us, and our reputation plays no small part in the influence we have on those around us. For this reason we are obliged not to injure our neighbor in his person or property, and we ought to be very mindful of his good name and reputation. We should always have a just regard to truth and charity to our neighbor. Who is our neighbor? Our neighbor is whomever it happens at any time to be in our power either to injure or do kindness to; who can, in any respect, become better or worse, or receive any hurt or any benefit, by our behavior towards them. So why is it that we see so much damage brought upon men in the form of slander, calumny, backbiting, and other evil speaking?

What are some of the causes of evil speaking?

1. One of the deepest and most common causes of evil speaking is ill nature and a cruel disposition. A person that is good-natured and has a pleasant disposition has more of a tendency to do what is best for their neighbor. But a person that is ill-tempered is always on the lookout to catch his neighbor at their worst.
2. Pride, ambition, and inordinate self-love. People think there is something to be gained by it. Vanity is the chief motive of detraction.
3. Related to pride and ambition is envy. People cannot endure the prosperity or happiness of others so they will do anything to dismiss their rivals in order to advance themselves.
4. Malicious revenge and spite. In the heat of the moment, men lose sight of the truth and may speak evil of others in revenge for some injury, either real or perceived, that they have received from them. In that moment, they don’t particularly care whether what they are saying is true or not.
5. Sense of weakness, want of courage, or despondency of his own ability.
6. Evil conscience.
7. Curiosity. Just a good old itch for talking and meddling in the affairs of other men, or any bad thing that is talked of in good company.

Now, there are several reasons for which Christians should be exhorted to refrain from evil speaking. In the first place it is a sin against God, who has forbidden us to bear false witness against our neighbor and to speak evil of others without a cause ( Eph 4:31). It is contrary to the command to love our neighbor. People are very reluctant to judge evil of themselves. Therefore, if they loved their neighbor as themselves, love would have the same tendency towards them. It is contrary to the command to be at peace with one another. Another reason is it can harm a person of the best treasure they have in this world - their name and reputation (Prov 22:1; Eccl 7:1). We should never be too eager to publish the faults of others, for we can never discern the exact nature and degree of their faults. How little can we understand the conditions, the environment or the temptations of those who fall into sin. We should never pronounce a sentence against our brother based on suspicion or rumour, without sufficient evidence. How easy it is to say something about someone that may be true, yet misrepresent them and bring reproach upon them that far exceeds their offence. There is one area that is always concealed to us and that is the area of motive. Therefore, how can we ever know if we are judging them too harshly? None of us are better than the law requires, none of us is any better than we ought to be. We have all sinned and come short of the glory of God. Much of the time the faults that we are so prone to point out in others are those that are most deeply seated in ourselves. Tell me the general drift of a man’s criticisms and I will show you his pet sin. We should never get used to talking about the faults of our neighbors. We are repeatedly warned against judging our neighbor (Matt 7:1-2; Rom 14:3,4; 1Cor 4:5). It is simply mean and shameful; it produces much harm in society, and is a reason for many people living their lives hating one another and dying in the same unfriendly disposition. Another reason to refrain from evil speaking is that we can actually cause great harm to ourself. We can actually lay a foundation for our own reproach. Of all the bad habits that we can have, those of the tongue are the hardest to cure. It is a common and widespread fault, and few are entirely free from it. It is not confined to wicked and profane persons; it is to be found in some measure even in those who lead virtuous lives, who love their friends and are active to serve them. Whoever is inclined to often speak evil of others gives a bad character of himself, even to those whom he desires to please. If they are wise enough, they will eventually come to the conclusion that the evil speaker is most likely speaking of them to others as he does others to him and they will come to view the evil speaker with disdain. 1 Cor 6:10 says that railers and revilers will not enter into the kingdom of heaven. Rash and undue judging of others, when we are guilty ourselves, makes us liable to a greater judgment (Rom 2:3). Far better is it for us to say nothing at all rather than speak evil of another person.

SOME RULES AND DIRECTIONS FOR THE PREVENTION AND CURE OF THIS GREAT EVIL.

1. Never say any evil of any man, but what we know to be absolutely true.

2. Before we speak evil of any man consider whether he has extended us some real kindness, and then consider how our words would affect him.

3. Let us learn to pity the faults of men, and to be truly sorry for them, and then we will take no pleasure in talking about them.

4. Whenever we hear something negative being spoken about someone, let us say something good about them.

5. Let us never be satisfied or take pleasure in listening to the gossip and rumors about another person.

6. Let us mind own business to the extent that the Lord commands us. Let us pay attention to our own obedience to the Lord. If our greatest concern is with ourselves, then we will find little occasion to be preoccupied with the affairs of someone else or to pronounce sentence on them (1 Cor 4:5). We need to look at our own hearts and see if they need to be cleansed of pride which makes us speak disdainfully of others. Gal 6:1 warns us to consider ourselves. How is it with us? Gracious hearts are always looking inward. We should always be the most inquisitive about our own sins and most severe against ourselves. If we do this we will find that we have little time to talk about others.

7. Lastly, let us set a guard before the door of our lips. Let us not speak without thinking first, so that the words that we speak will be pleasant, edifying for the building up of our neighbor.

Especially when we speak of others we need to consider what we are going to say and use great caution with our words. We need to pay attention to who we are speaking to. And above all, remember, that once our words are out of our mouth they are forever out of our power to control them.

Closing

In its earliest stages a fire can be quenched with a pint of water, but when it begins to spread who can set bounds to it? The sin of slander is like a maddened horse or a dry forest on fire. A thoughtless scandalous word goes from one to another gathering as it goes. A snowball rolled in snow gathers garbage and whatever may come in its way, becoming solid by rolling and lasting long after all other snow has melted. So when a gossiping tongue drops a hint a whole area of peace may be destroyed for long (F. Hastings).

Chapter 10: Temporary Abatement of Religious Attention - Letter to Mr. Bellamy - Missionary Tour

And furthermore we promise, that we will not allow ourselves in backbiting; and that we will take great heed to ourselves to avoid all violations of those christian rules, Titus 3:2. 'Speak evil of no man;' James 4:11. 'Speak not evil one of another, brethren;' and 2 Cor 12:20. 'Let there be no strifes, backbitings, whisperings;' and that we will not only not slander our neighbour, but also will not feed a spirit of bitterness, ill will, or secret grudge against our neighbour, insist on his real faults needlessly, and when not called to it, or from such a spirit, speak of his failings and blemishes with ridicule, or an air of contempt.

(from Works of Jonathan Edwards, volume 1, PC Study Bible formatted electronic database Copyright © 2004 by Biblesoft, Inc. and Ages Software, Inc. All rights reserved.)