Burning lips and a wicked heart - Splendid, shining, smooth lips; that is, lips which make great professions of friendship are like a vessel plated over with base metal to make it resemble silver; but it is only a vile pot, and even the outside is not pure.
Burning lips - i. e., “Lips glowing with, affection, uttering warm words of love,” joined with a malignant heart, are like a piece of broken earthenware from the furnace, which glitters with the silver drops at stick to it, but is itself worthless.