When he speaketh fair, believe him not. When he lowers his voice to a winning, agreeable tone, put no trust in him. Septuagint, "If thine enemy entreat thee with a loud voice, be not persuaded." For there are seven abominations in his heart.
His heart is filled with a host of evil thoughts (see on Proverbs 26:16), as if seven devils had entered in and dwelt there. Ecclesiastes 12:10, etc. "Never trust thine enemy; for like as iron rusteth, so is his wickedness.
Though he humble himself, and go crouching, yet take good heed and beware of him." Plato's verdict concerning hypocrisy is often quoted, ἐσχάτη ἀδικία δοκεῖν δίκαιον εἶναι μὴ ὄντα "It is the very worst form of injustice to appear to be just without being so in reality".
With this Cicero agrees ('De Offic.,' 1.13), "Totius injustitiae nulla capitalior est quam eorum, qui tum cum maxime fallunt id agunt ut viri boni esse videantur."