Two Words
The moment when Javert meets 24601 in the sewers and 24601 commands him to look down, to see the boy he is carrying, is the moment Javert realizes that the tables have turned.
In that moment, "look down" becomes not an order from police to prisoner, but from one man to another.
For twenty years Javert chased 24601, thinking of the escaped prisoner as a being at a far lower level than him. It was the natural order of things.
And with two words, 24601 becomes Jean Valjean, a man just like Javert. With two words, they have become equals.
And Javert knows that that's not how it should be. He needs to be in charge. That's the order of the world.
And if order leaves his life, what else does Javert have to live for?