if you have read the bible, the first testament speaks mainly as god as the "ruler" of the people, with no mercy and forgivness.

Once you hit the new testament and the comming of jesus, we see a total turn around as god being a savor, and he with all the mercy and forgivness.

It was made this way so we see the mercy limits of god, we have a lifetime of mercy, but on our day of judgement god has no mercy.

Personally i think its a load of BS, because any god whom tests his people through human sacrifice is just wrong.

From the teachings of Abraham we can see the controversy instilled when God asked him to kill his child in the name of god, Abraham with the ax in his hand about to do it, and god say's you have proven your love to me.