Proverbs 26:23-26 DBY

23 Ardent lips, and a wicked heart, are [as] an earthen vessel overlaid with silver dross.
24 He that hateth dissembleth with his lips, but he layeth up deceit within him:
25 when his voice is gracious, believe him not, for there are seven abominations in his heart.
26 Though [his] hatred is covered by dissimulation, his wickedness shall be made manifest in the congregation.