Ones biggest strength can also be ones biggest weakness
It’s on’y a mouse, George (5)
Uh-uh. Jus’ a dead mouse, George (5)
A mouse? A live mouse? (5)
Lennie gets picked on by Curley and Lennie crushes Curley's hand
Curley sat down on the floor, looking in wonder at his crushed hand. (64)
Lennie accidentally kills newborn puppy.
Why do you got to get killed? You ain’t so little as mice. I didn’t bounce you hard,(85)
Steinbeck suggests that already early on in the book Lennie is showing signs of his strength. He shows Lennie’s strength by letting the reader know that he killed a small little mouse. Not knowing that he killed the mouse Lennie was incapable of controlling his strength.
Lennie breaks Curley's wife's neck
And then she was still, for Lennie had broken her neck, (91)
When Curley went all out on Lennie and starting making Lennie bleed, George immediately was yelling to get Curley. Ths Lennie crushing Curley's hand. This time being bigger in size, Curley’s hand was the victim of Lennie’s brute strength. Steinbeck reveals Lennie’s strength with objects getting bigger and bigger throughout the storyline.
When Lennie was playing and petting the puppy he wasn’t trying to hurt it, he was just incapable of understanding that he is too strong to play with such delicate things like body parts or small animals.
Look out, now you’ll muss it. And then she cried angrily, You stop it now, you’ll mess it all up. (91)
With all of the things Lennie has killed or injured, everything was increasing in size until finally, Lennie kills Curley’s Wife. Lennie first killed a small mouse then crushed Curley’s hand afterward he killed the puppy, and finally, he broke Curley’s wife’s neck ultimately killing her. Seeing the progression of the size makes me believe that Steinbeck wants to prove how strong Lennie actually is by showing the variety in sizes.