"Whatever you do, it will be you who do it – not your mother." (445)

This is pretty much the central message of the entire book. The book has already dealt with themes like free will and the nature vs nurture debate. And in this sentence, Lee is able to connect both of them. There never was a nature vs nurture debate. Because if you were to buy into people behaving because they were born that way, it would be like the King James translation of the bible – "Thou shalt" (301). You will inevitably make those decisions, and it is predetermined by fate. On the other hand, if you were to believe that you came from nurture, that is a parallel to the American Standard translation – that you were "ordered" by your parents to behave the way you behave. So, if you behaved badly, that was because you had bad parenting, and your parents should also be blamed. But, Steinbeck rejects both of these theories. And instead, he argues that it doesn't matter. It doesn't matter if you had bad parents, or were born to an evil parent (Cathy). Whatever action you take, it's your responsibility. You can't blame your actions on your nature, or your nurture. You can only blame yourself. This is where the Hebrew word timshel comes in: Thou mayst. You could overcome your past, or you can't. Either way, it's ultimately your choice. Nothing is forever, and you can break the cycle.