Tzvi,
This particular verse in Exodus 20:1-6 makes me wonder sometimes:
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1 And G-d spoke all these words, saying: {S} 2 I am the LORD thy G-d, who brought thee out of the land of Egypt, out of the house of bondage. Thou shalt have no other gods before Me. 3 Thou shalt not make unto thee a graven image, nor any manner of likeness, of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth; 4 thou shalt not bow down unto them, nor serve them; for I the LORD thy G-d am a jealous G-d, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate Me; 5 and showing mercy unto the thousandth generation of them that love Me and keep My commandments. {S} 6 Thou shalt not take the name of the LORD thy G-d in vain; for the LORD will not hold him guiltless that taketh His name in vain. {P}
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This is difficult to understand how Hashem 'visits the iniquity of the fathers upon the children'. I forget the explanations but this verse often makes me wonder.
I also need to learn why Jobs daughters and sons were killed in order to test Job.