<<If God is all powerful as
people claim, then he didn't have to kick them out, nor did he have to
allow evil to exist.>>
The problem with this argument is that it assumes a divine perspective ("I can
see no reason for evil to exist, therefore God can have no good reason"). The
theistic answer is that this is not the best of all possible worlds (we CAN
see this) but it is the best of all possible ways to achieve the best of all
possible worlds (this we CANNOT see, not yet). IOW, "an imperfect moral world
is the necessary precondition for achieving the morally perfect world" (Norman
Geisler).
The strongest counter argument comes from, e.g., Mackie, viz., God could have
created free beings who never choose to sin. I think Alvin Plantinga has done
the best job of answering that.
<< By arguing this way, you show the atheists are right.>>
How so? Atheists are right only in pointing out the existence of evil. With
that theists agree. But they are not right about that being proof of the
non-existence of God, or the non-necessity of its provisional existence for
the greatest good.
<<How do you explain the unimaginably painful command God gave to sacrifice
one's own son to Him?>>
Easy. Abraham had the divine perspective. He trusted God. God had promised him
that through Isaac would come a great nation. Therfore, Abraham reasoned, even
after sacrificing Isaac, God would bring him back from the dead. That is in
fact what God did, figuratively. He did it literally much later, with Jesus.
So Abraham did not commit the fallacy of thinking only from a limited
perspective. And his faith was rewarded.
Jim