The last Parsha of the Book of Vayikra is one of two examples of a brief promise of good things if we obey God followed by a long dire warning of what will happen if we disobey.
To us it seems strange that the Torah goes into such a lengthy litany of horrible things that will befall us. Did God or Moses really believe that people would respond to such threats? Should we think of religion as having a sword suspended over our heads? Isn’t doing something for its own sake preferable to doing it out of fear of punishment? And yet too often religion is viewed in such terms.
Perhaps the graphic list of bad things worked in those days. People looked to their kings and gods to protect them from invasion, famines and other disasters. Really the Torah is simply repeating a well-known formula that can be found throughout Mesopotamian cultures in the “contracts” or treaties that kings made with their subjects and vassals. A mutual arrangement for benefits that if broken enabled one to transfer one’s loyalty to a new ruler who might do a better job.
The fact is that throughout the Torah God is described as a zealous, demanding God who remembers sins of fathers and carries them on to future generations. Now this contradicts the Torah itself in Deuteronomy (24.17) that says “Fathers shall not die for sons, sons shall not die for their fathers. A person is punished only for what he does wrong.”
I understand the idea of remembering sins, Poked Avon Avot, as meaning that there are consequences to what parents and children do that can affect badly and impact future generations. And conversely good actions, responsible parents and children can significantly add positive influences. And this is another way of putting it this long chapter 26. We have been warned!