Slander: on not Being Quick to Put Faith in it (19-20)

As you see, flattery and slander were most likely to find an opening when they were framed with reference to Alexander's weak point. In a siege the enemy do not attack the high, sheer and secure parts of the wall, but wherever they notice that any portion is unguarded, unsound or low, they move all their forces against that place because they can very easily get in there and take the city. Just so with slanderers: they assail whatever part of the soul they perceive to be weak, unsound and easy of access, bringing their siege-engines to bear on it

The engines that they use against the hearer are deceit, lying, perjury, insistence, impudence, and a thousand other unprincipled means; but the most important of all is flattery, a bosom friend, yes, an own sister to slander. Nobody is so high-minded and has a soul so well protected by walls of adamant that he cannot succumb to the assaults of flattery, especially when he is being undermined and his foundations sapped by slander.