We see in this a worthless vessel, covered with glaze to make it seem from the outside to be very valuable. If you are looking at this from the spiritual standpoint, it makes it appear to be redeemed (glaze). This person, mentioned here, has beautiful burning lips which seem to be affectionate. They are a deceit coming from a wicked heart.
A cheap veneer of glaze over a common clay pot hiding its commonness and fragility is like the deception spoken by evil people. The point is this: just as glaze covers the rough pottery but cannot ultimately change its character, so the evil man cannot change his character by covering it with eloquent speech. This thought is expanded (in verses 24 to 28).
Under Gods command 