Jeremiah 9:5

They will deceive, Heb. mock, or deride; they are scoffers. They have taught their tongue to speak lies; they have so framed their tongues to it by custom and constant use, that lying is become so familiar to them that they cannot leave it. The same word is applied to the wild ass, used or taught to the wilderness, Jeremiah 2:24, Jeremiah 13:23. Weary themselves to commit iniquity; they use a great deal of industry, diligence, and contrivance in it, Psalms 7:14 Isaiah 5:18. They spare for no labour and feel no weariness in it, whereby they are become expert.