What are Boxer's maxims in Animal Farm? And, what causes the animals to finally rebel against Mr. Jones and his four farmhands?

Boxer's most famous maxim is:

I will work harder.

As the book moves on, you will find him also use the maxim:

Napoleon is always right.

Each of these are indicative of his character a hard-working and loyal contributor to a society.

Mr. Jones' neglect of the animals needs of food and care(like the cows needing to be milked) caused them to rebel. His neglect arose from a drunken stupor.