This passage contains Godly advice concerning gossip. The first piece of advice is to remove the source that feeds the fire (vs 20); next, do not add further kindling to already hot coals so as to restart the fire. Hot coals will remain hot for some time, but will eventually cool.
An argumentitive individual will not only stir up coals that have been left to cool, but will add more fuel so as to re-kindle strife (vs 21). Verse 22 reminds us that the talebearer's words (gossip) hurt deeply and his lips are quick to carry a 'hot topic'. The source is a wicked heart. Such is likened to broken pieces of pottery covered not with refined and purified silver, but with silver dross, i.e., the off-scourings, the impurities of silver which are left after the purifying process. Such words are useless and have no value (vs 23).
Verses 24-26 tell us that the person who causes such trouble cannot be trusted when he speaks fair words because his fair words cover a deceitful heart, his hatred is masked, but his evil intentions will eventually be revealed to all.
Verse 27 is a proverb teaching that evil planned for another will be recompensed upon the one who plans the evil.
Verse 28 seems a summary of results coming upon the one whose tongue is loose and spiteful.
The book of James speaks of the unruly tongue and indicates it's use for good and potential for evil, lamenting that such can & does come from the same mouth.
Proverbs 25:21-22 teaches that we are to repay evil with kindness, the resulting act will be like 'heaping coals of fire on his head'. This behavior may be understood in two ways. (1) The idea is that of repaying wrong doing with kindness, causing the offender to become unsettled in their minds as to your behavior and change their opinion of you, or, (2) it refers to a practice common in those days when a coals was kept burning in the hearth so one could more easily kindle a fire for warmth of cooking. At times, the coals would go out and one would go to a neighbor for coals, which were carried home in a pot. Customarily, people in the culture of the Bible carried burdens carefully balanced on their heads, so the idea is that returning kindness for ill treatment is like giving to one in need, regardless of their treatment to you.
When we respond in kind to harsh treatment or gossip, we add fuel, making the situation worse. To put out the fire, we remove the source and treat the person with love and kindness. When they have a need, we should come to their aid, rather than ignore their situation.
Jesus summed up this teaching in what we call the Golden Rule when He said, in Matt 7:12
Therefore all things whatsoever ye would that men should do to you, do ye even so to them: KJV
Adolph Baumbach took the words from Psalm 19:14 and set them to music, I am sure you know the tune...take a moment to sing it and prayerfully consider.
"Let the words of my mouth and the meditation of my heart be acceptable in Thy sight, O Lord..."