The boy who becomes king is said to have killed a wolf with his spear. This has nothing to do with the plot of the movie, except that the boy hides in a narrow pass, like the Greeks did, & lets the wolf impale himself on his spear, like the Greeks let the Persians get themselves killed by attacking at Thermopylae. You can say the boy defended himself reasonably. Even that this shows the superiority of defensive warfare.
But the man who gave the laws to the Spartans was called Lykurgos, the one who keeps the wolves away. The story leaves no doubt, one must be a wolf to fight a wolf. The children of Spartan women did not live if they showed weakness at birth. They did not live unless they learnt to control their fear & to inflict more punishment than they received.
The Spartans’ belief in their laws alone could keep their armies together. No man, nor even a few could overpower all the others. At the same time, killing weak infants & the Spartan education caused numbers to dwindle, so that no man could be spared in civil strife. The necessity to master those who do the works necessary to build & maintain even a modest town gave work to all warriors. Their dedication to Sparta made even commerce with others impossible.
It is shocking to see just how isolated Sparta was, & how small. The difficulty of survival is magnified this way. There is no hiding that women, even queens, would never have allowed to have their boys thrown into the wilderness. No hiding that, being that there are laws, young men must be punished harshly thereafter. So this is why Spartans earned such fear & admiration, because the freedom of Sparta depended on their obeying the laws fearlessly.
King Leonidas does very little to teach his boy, but from such a man, not very much is needed. He insists, nevertheless, on saying this, that a Spartan should above all show honor & respect. The boy should therefore acknowledge his betters & his equals, so to speak. His life, Leonidas says, depends on the man next to him. Spartans more than others need to stay together.
The proud Spartan king is more aware than others of the importance of reputation. Being seen to maintain Spartan orders inviolate is his best title to the kingship, & his son’s after him. Refusing to fight or not leading the war would be both foolish & dangerous. It seems, politics proves without any great difficulty that the manly man is more realistic than the coward. Perhaps Sparta shows the political life so well because it shows leadership is obedience.