Proverbs 26:23
“Burning lips and a wicked heart are like a potsherd covered with silver dross.”
As coals are to burning coals, and wood to fire; so is a contentious man to kindle strife.
The words of a talebearer are as wounds, and they go down into the innermost parts of the belly.
Burning lips and a wicked heart are like a potsherd covered with silver dross.
He that hateth dissembleth with his lips, and layeth up deceit within him;
When he speaketh fair, believe him not: for there are seven abominations in his heart.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Cross-References
“Faithful are the wounds of a friend; but the kisses of an enemy are deceitful.”
“Be not hasty in thy spirit to be angry: for anger resteth in the bosom of fools.”
“And while he yet spake, behold a multitude, and he that was called Judas, one of the twelve, went before them, and drew near unto Jesus to kiss him.”
“Draw me not away with the wicked, and with the workers of iniquity, which speak peace to their neighbours, but mischief is in their hearts.”
“He that hideth hatred with lying lips, and he that uttereth a slander, is a fool.”