mP: Its funny how so many jewish kings ruled 40 years. Saul , David, Solomon, Moses , thats obviously utterly stupid.
Good point, but I think we have to consider manipulation. Case in point the 70 years of exile and the sabbath payback of the land. It is exactly 70 years after the people were deported off the land. But it took some time after the fall of Jerusalem and the conquering of the other cities to completely empty the land. The deportation of the nations out of that region took up to 23 years. That is, Daniel was first deported in the accession year of Nebuchadnezzar and the last deportation was in year 23.
But there was some fine tuning. Some people were left in the land after the fall of Jerusalem and the last major deportation in year 18. Then the main remnant of the Jews ran down to Egypt, leaving at least the land of Judah completely desolate of people after Gedeliah died in year 20 of Nebuchadnezzar II. So that would have ordinarily begun the 70 years of desolation, at least for Judea. But God commanded the Jews to return to Judea, which they didn't. They were thus killed and a small remnant did return to Judea in year 23, being deported that same year. (Jer. 44:14,28) By this time, likly a small remnant of other peoples were all that were left that needed to be deported from the Northern Kingdom area as well.
Thus I would think it is possible that the precise times of the death of these kings being precisely 40 has some significance. In the meantime, it would not have been difficult for Jehovah to extend the lives of certain kings so that their rules ended after 40 years. The period of Saul, David and Solomon is a period of 120 years, the same as a generation of Noah's day. So maybe there is a hidden message for this period for these kings. I favor divine manipulation vs. simply coincidence, though.