The words of his mouth are iniquity and deceit: he hath left off to be wise, and to do good.

The words of his mouth are iniquity and guile : he would not understand that he might do well.

The words of his mouth are wickedness and deceit: he hath left off to be wise, to do good.

The words of his mouth are iniquity and deceit, He ceased to act prudently, to do good.

In the words of his mouth are evil and deceit; he has given up being wise and doing good.

For it flattereth him in his eyes, Until his iniquity be found, and he be hated.

The words of his mouth are iniquity and deceit. The two clauses of this verse may be understood as referring to the same thing, namely, that the wicked indulging in deceit and vanity, will not receive or admit the light of understanding. This, I apprehend, is the meaning of David. He reproves the wicked not merely for circumventing others by their wiles and stratagems, but especially because they are altogether destitute of uprightness and sincerity. We have already said that the Psalmist is here speaking not of sinful and wicked men, in whose hearts there still remains some fear of God, but of the profane despisers of his name, who have given themselves up entirely to the practice of sin. He therefore says that they have always in their mouth some frivolous excuses and vain pretexts, by which they encourage themselves in rejecting and scoffing at all sound doctrine. He then adds, that they purposely suppress in themselves all knowledge or understanding of the distinction between good and evil, because they have no desire to become better than they are. We know that God has given understanding to men to direct them to do what is good. Now David says that the wicked shun it, and strive to deprive themselves of it, that they may not be constrained to repent of their wickedness, and to amend their lives. We are taught from this passage, that if at any time we turn aside from the path of rectitude, the only remedy in such a case is to open the eyes of our understanding, that we may rightly distinguish between good and evil, and that thus we may be led back from our wandering. When, instead of doing this, a man refuses instruction, it is an indication that he is in a state of depravity altogether desperate.

The words of his mouth are iniquity and deceit - Are false and wicked. See the notes at Psalm 12:2. It is words do not fairly represent or express what is in his heart.
He hath left off to be wise - To act wisely; to do right.
And to do good - To act benevolently and kindly. This would seem to imply that there had been a change in his conduct, or that he was not what he once professed to be, and appeared to be. This language would be applicable to the change in the conduct of Saul toward David after he became envious and jealous of him 1 Sam. 18; and it is possible, as Amyraldus supposed, that this may have had particular reference to him. But such instances of a change, of feeling and conduct are not very uncommon in the world, and it may doubtless have happened that David experienced this more than once in his life.

The words of his mouth are iniquity - In the principle; and deceit calculated to pervert others, and lead them astray.
He hath left off to be wise, and to do good - His heart is become foolish, and his actions wicked. He has cut off the connection between himself and all righteousness.

The words of his mouth [are] iniquity and (c) deceit: he hath left off to be wise, [and] to do good.
(c) The reprobates mock wholesome doctrine, and put no difference between good and evil.

The words of his mouth are iniquity and deceit,.... Not only sinful, but sin itself; his mouth is full of cursing and bitterness, of filthy and unchaste words, of corrupt communication, lying, deceit, and flattery; out of the abundance of the wickedness of his heart his mouth speaketh; and which shows the badness of it, and proves all that is said before of him;
he hath left off to be wise, and to do good; by which the psalmist seems to intend one that had been a professor of religion, who, besides the light of nature he had acted contrary to, had had the advantage of a divine revelation, and had been enlightened into the knowledge of divine things, and had done many things externally good, particularly acts of beneficence; but now had dropped his profession of religion, denied the truths he had been enlightened into, and ceased from doing good; otherwise a natural man understandeth not; and, though he is wise to do evil, to do good he has no knowledge.

Left off - Once he had some degrees of wisdom, but now he is become an open apostate.