The lips of the righteous know what is acceptable - And what they believe to be most pleasing and most profitable, that they speak, but the wicked man knows as well what is perverse, and that he speaketh forth. As the love of God is not in his heart, so the law of kindness is not on his lips.

know

Ecclesiastes 12:10 The preacher sought to find out acceptable words: and that which was written was upright, even words of truth.

Daniel 4:27 Why, O king, let my counsel be acceptable to you, and break off your sins by righteousness...

Titus 2:8 Sound speech, that cannot be condemned; that he that is of the contrary part may be ashamed, having no evil thing to say of you.

but

Proverbs 11:11 By the blessing of the upright the city is exalted: but it is overthrown by the mouth of the wicked.

Proverbs 12:6,18 The words of the wicked are to lie in wait for blood: but the mouth of the upright shall deliver them...

Proverbs 15:2,28 The tongue of the wise uses knowledge aright: but the mouth of fools pours out foolishness...

Proverbs 18:6-8 A fool's lips enter into contention, and his mouth calls for strokes...

frowardness

Sanctions of Moral Law, Natural and Governmental.
In the discussion of this subject, I shall show-- I. What constitute the sanctions of law. 1. The sanctions of law are the motives to obedience, the natural and the governmental consequences or results of obedience and of disobedience. 2. They are remuneratory, that is, they promise reward to obedience. 3. They are vindicatory, that is, they threaten the disobedient with punishment. 4. They are natural, that is, happiness is to some extent naturally connected with, and the necessary consequence of, …
Charles Grandison Finney—Systematic Theology

How the Simple and the Crafty are to be Admonished.
(Admonition 12.) Differently to be admonished are the simple and the insincere. The simple are to be praised for studying never to say what is false, but to be admonished to know how sometimes to be silent about what is true. For, as falsehood has always harmed him that speaks it, so sometimes the hearing of truth has done harm to some. Wherefore the Lord before His disciples, tempering His speech with silence, says, I have many things to say unto you, but ye cannot bear them now (Joh. xvi. 12). …
Leo the Great—Writings of Leo the Great

Letter xv (Circa A. D. 1129) to Alvisus, Abbot of Anchin
To Alvisus, Abbot of Anchin He praises the fatherly gentleness of Alvisus towards Godwin. He excuses himself, and asks pardon for having admitted him. To Alvisus, Abbot of Anchin. [18] 1. May God render to you the same mercy which you have shown towards your holy son Godwin. I know that at the news of his death you showed yourself unmindful of old complaints, and remembering only your friendship for him, behaved with kindness, not resentment, and putting aside the character of judge, showed yourself …
Saint Bernard of Clairvaux—Some Letters of Saint Bernard, Abbot of Clairvaux