Matthew Henry Commentary Proverbs 26:24-26

"He that hateth dissembleth with his lips; But he layeth up deceit within him: When he speaketh fair, believe him not; For there are seven abominations in his heart: Though [his] hatred cover itself with guile, His wickedness shall be openly showed before the assembly." — Proverbs 26:24-26 (ASV)

Always distrust when someone speaks smoothly unless you know them well. Satan, in his temptations, speaks smoothly, as he did to Eve; but it is madness to believe him.