4 ideas
Plutarch argues in his dedication to Trajan that a leader's great actions are often shaped by fortune, circumstance, and other people. Their spontaneous remarks under pressure are less contaminated by chance, so they show a person's actual disposition more directly. That makes a collection of brief sayings a compressed record of character, useful where full biographies are too long to study.
A poor laborer with nothing else to give scooped water from a river in his hands and offered it to the Persian king Artaxerxes, who received it graciously. The principle is that accepting small gifts warmly is as kingly as giving great ones, because it honors the giver's goodwill rather than the value of the gift. Plutarch uses the story to frame his own modest book as an offering to the emperor.
Philip of Macedon said that any fortress could be taken if a donkey loaded with gold could make its way up to it. The lens shifts security from physical barriers to the incentives of the people who guard them. A defense is only as strong as its most corruptible insider, so bribery can accomplish what siegecraft cannot.
When a poet flattered Antigonus as the son of the Sun god, the king replied that the servant who carried out his chamber pot knew otherwise. The retort deflates flattery by pointing to people who see a ruler's bodily, ordinary life. Those closest to a leader's daily reality are immune to the myth, and a wise ruler keeps that perspective himself.