How does steinbeck maintain the tension and suspense in the scene (book mice and men)

By telling a little about Lenny's ( I think that's his name, I read this book in 9th grade ) background we know he has a mental illness so when he does something we get suspense and tension. We also keep hearing George tell Lenny the same thing over and over so that creates a sort of suspense and tension. I hope this helped! It really is a good book!