Aristotle says in Nicomachean Ethics II.9, while discussing how we must be careful to stay in the path of virtue which is the mean between two vices:
And in everything we must beware above all of pleasure and its sources, for we are already biased in its favor when we come to judge it. Hence we must react to it as the elders reacted to Helen, and on each occasion repeat what they said; for if we do this, and send it off, we shall be less in error.
What legend about Helen (I assume it's Helen of Troy?) is he referencing here? Which city's elders is he speaking of, and what did they say when sending her away?
I believe they are referencing the Iliad, Book 3, lines 150-160. Helen looks on at the Greeks (Achaeans) from the walls of Troy. The Trojan elders say to each other that they should send Helen back to the Greeks so that they can end the war. They remark upon how beautiful she is, but that they must disregard that and send her back, for the good of the city. In Artistotle's day, the Iliad and the Odyssey were discussed and referred to as great sources of wisdom in how to act and deal with issues. Of course, she wasn't sent away--King Priam decided to keep her there, despite the words of the elders.
Here's one translation:
The two sages, Ucalegon and Antenor, elders of the people, were seated by the Scaean gates, with Priam, Panthous, Thymoetes, Lampus, Clytius, and Hiketaon of the race of Mars. These were too old to fight, but they were fluent orators, and sat on the tower like cicales that chirrup delicately from the boughs of some high tree in a wood. When they saw Helen coming towards the tower, they said softly to one another, "Small wonder that Trojans and Achaeans should endure so much and so long, for the sake of a woman so marvellously and divinely lovely. Still, fair though she be, let them take her and go, or she will breed sorrow for us and for our children after us."