Bridges on Proverbs 20:19
Charles Bridges on Proverbs 20:19

19.  He that goeth about as a talebearer revealeth secrets: therefore meddle not with him that flattereth with his lips. {flattereth: or, enticeth}
Never let us forget that all intercourse of social life must be based on love. Any breach of this is highly displeasing to God. Witness the talebearer. Unhappily he has much time on his hands unemployed for any good purpose. Hence he spends it on other people’s business; ferreting out secrets, or diving into family arrangements. All this is material for scandal, or for idleness. In his visit he talks of the affairs of the last family. His present visit will furnish matter for idle talk in the next house. And thus his name describes his work, indulging an impertinent curiosity; making a tale of everything he sees or hears. It is the business of his life, for which all other business is sacrificed, as if the whole man were one tongue, as if, in its restless babbling, it had discovered the grand secret of perpetual motion. Such a one — meddle not with him. We would not wish him to look over our wall; much less to enter into our houses; least of all, to associate with our family circle, where his whole employment would be, either to draw out, or to put in, what “was not convenient.”†
The flagrant blot, however, in this contemptible, yet dangerous character, is his unfaithfulness — going about — revealing secrets. (Chapter 11:13.) This is peculiarly offensive to a God of truth. Even when matters have been given to him under a seal, his restless irritation breaks through the feeble bond. He ‘dismantles and rends the robe from the privacies of human intercourse. Who entrusts a secret to his friend, goes thither as to a sanctuary; and to violate the rites of that, is sacrilege and profanation of friendship.’† Never let us think this to be a trifle. Never let us undertake a trust without the most resolute determination of Christian faithfulness.
Observe his other names — flattering with his lips. Thus he insinuates himself into the secrets of the unwary, and gains his materials for talebearing; flattering the present at the expense of the absent. Watch and pray earnestly against this deadly evil. Keep thine own vineyard carefully.† Else if thine eye be abroad, when it ought to be at home, it will be, like “the vineyard of the slothful, full of thorns and nettles” (Chapter 24:30, 31); like the ‘curious people,’ whom Augustine rebuked, who ‘pry into another’s heart and life, but are slothful to amend their own.’† Be diligent in your own calling, serving the Lord and his church. Study the obligation of Christian character, according to the standard of the Divine Exemplar, whose every word was fraught with the flowing of love. Oh! how many in self-indulgence and forgetfulness of their own obligations, because they have no employment for their hands, set their tongues to work! (1 Timothy 5:13.) Such men bring, as it were, the plague of flies with them (Exodus 8:24); buzzing from house to house, from one neighbor to another, all the report of evil heard or done. A sharp reproof is their just desert, and an effectual means of driving them away. (Chapter 25:23.)