(5) Deceive.--The word is commonly translated, as in the margin, mock. (So in 1Kings 18:27; Judges 16:10; Judges 16:13; Judges 16:15.) The context here shows, however, that the kind of mockery is that which at once deludes and derides; and as the former meaning is predominant, the text of the English version had better stand as it is.

To commit iniquity.--Literally, to go crookedly, or, in the strict sense of the word, to do wrong.

Verse 5. - They have taught their tongue, etc.; again an intimation of the unnaturalness (in the higher sense) of vice (comp. on Jeremiah 2:33).

9:1-11 Jeremiah wept much, yet wished he could weep more, that he might rouse the people to a due sense of the hand of God. But even the desert, without communion with God, through Christ Jesus, and the influences of the Holy Spirit, must be a place for temptation and evil; while, with these blessings, we may live in holiness in crowded cities. The people accustomed their tongues to lies. So false were they, that a brother could not be trusted. In trading and bargaining they said any thing for their own advantage, though they knew it to be false. But God marked their sin. Where no knowledge of God is, what good can be expected? He has many ways of turning a fruitful land into barrenness for the wickedness of those that dwell therein.And they will deceive everyone his neighbour,.... In conversation, with lying words; and in trade and commerce, by art and tricking:

and will not speak the truth; with respect to facts they report, or goods they sell:

they have taught their tongue to speak lies; and become so accustomed to lying that they cannot do otherwise; it is as it were natural to them:

and weary themselves to commit iniquity; spared no pains to come at it, nor any in it, and go on even to weariness; are more laborious and indefatigable in committing sin than good men are in doing good; which shows great folly and stupidity. The Targum is,

"they are become foolish, they have erred.''