How could Moshe be so sure that Yisrael would rebel against Hashem after his death?
(31,27) “For I know your rebellious spirit and your stubbornness. Even whilst I am alive with you today you are rebelling against Hashem, all the more so after my death!…For I know that after my death you will surely become corrupted and deviate from the way which I have commanded you, and evil will befall you at the end of days because you did evil in the eyes of Hashem, to make Him angry through the work of your hands.”
Moshe’s argument that Yisrael would “all the more so” rebel against Hashem after his death needs to be explained. And how could he claim that “I know that after my death you will surely become corrupted”? Surely, this is something that depends on their freewill!
But the explanation is that their are two ways that a father can deal with his son when he wants to punish him. The first is to punish him immediately after every bad deed that he commits, and the second is to wait to punish him only after he has filled his measure of transgressions. The difference between these two approaches is that when the father punishes his son immediately he will take to heart the chastisement much more than the son whose father is promising to punish him sometime in the far future. As it says in Koheles 8:11 “Because the sentence of the evil deed is not executed swiftly, therefore the hearts of the children of men are encouraged to do evil”.
Now, during the days of Moshe Rabbeinu the way that Hashem conducted Himself with Yisrael was to chastise them and punish them immediately, like we find after the incident of the golden calf and of Korach. But after the death of Moshe punishment was meted out only infrequently.
This was Moshe’s argument - “Even whilst I am alive with you today you are rebelling against Hashem, all the more so after my death!…For I know that after my death you will surely become corrupted”. How do I know this? Because “evil will befall you at the end of days”, and not immediately, and so it is even more certain that you will sin after my death. If when I am alive you are sinning even though punishment comes immediately, all the more so will you sin after my death when your punishment will only be at the end of days.