Boxer actually adopts two mottoes. The first is, 'I will work harder.' He embraces this maxim as an answer to every problem or setback. His hard work inspires all the other animals and drives them to do more than they ever did. As such, work on the farm runs like clockwork. Boxer becomes the admiration of everybody on the farm.
This approach by Boxer becomes even more valuable at a time when his strength is needed in the construction of the windmill. He drags limestone to the top of the quarry for it to be dropped so that it may shatter into manageable pieces. The stones could then be used to build the windmill.
The second maxim he adopts is, 'Napoleon is always right.' Boxer displays unstinting loyalty to his leader and believes whatever he says. He hardly ever expresses doubt. When Napoleon, for example, declares that Snowball had been a traitor from the outset, Boxer accepts the truth of this statement merely on the basis of Napoleon having said it. His acquiescence and obedience are typical of the type of unquestioning loyalty displayed by those followers who are less educated or who lack the intelligence to question.
On the one occasion that Boxer does show some form of rebellion, such as when he questions Squealer about their victory over the humans after the windmill had been destroyed, he is regarded with suspicion. Not much later, Napoleon's dogs attack him but he easily drives them off, almost killing one, but letting it go on Napoleon's command.
Tragically, Boxer's utter dedication and loyalty receive scant regard and appreciation from his ruthless leader. When he falls ill after overworking and sustaining an injury, Napoleon sells him to the knacker (horse slaughterer) and buys a case of whisky from the proceeds. The noble Boxer dies an ignoble death.
"If Comrade Napoleon says it, it must be right" is one motto, and "work harder" is a second. Boxer represents the dedicated proletariate who is willing to work himself to death, believing blindly in his leaders.