Matthew Poole and continuators on Job 20:12

12. Though wickedness be sweet in his mouth , though he hide it under his tongue ;

i. e. To his tast, though it greatly please him for the present.

As an Epicure doth a sweet Morsel, which he is loath to swallow, and therefore keeps and rolls it about his mouth that he may longer enjoy the pleasure of it. Though he be highly pleased with his lusts, and cleave to them in hearty love, and resolve to hold them fast, and improve them to the greatest delight and advantage.