Bone asks some very good questions about the chilling story of Abraham and his willingness to sacrifice his son (found in Genesis chap. 22).
Bone asks:
<<"If I or you, dear reader, hear voices in the night telling us to kill our child should we act on them?  How could I be certain that the voice is Yahweh’s and not Beelzebub’s.  Is Abraham’s act an act of insanity?  Isn’t Yahweh’s request immoral? Would Abraham have been justified in responding, “My god is a loving and merciful god and wouldn’t ask me to do that.">> 
These are good questions, and defenders of the Christian faith have had considerable difficulty in responding to them (note especially that there is no uniformity in their answers to such questions). How would a believer like Abraham, when hearing a voice command him to do anything (much less than calling for him to sacrifice his son), distinguish this voice from his own emotions, desires or halucinations? In other words, by what means does the believer determine that it is God's voice, and not the voice of some competitor (as Bone suggests), or one's own derranged impulses? The Bible does not tell us what God's voice sounds like or how to make such distinctions, but according to the Genesis story, Abraham clearly recognized it to be God's voice somehow (or no how?).
Some believers, recognizing that such questions are surely valid if they expect non-believers to take their religious defenses seriously, will cite instructions from the New Testament, such as I John 4:1, which states: "Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world." Other believers caution that employing this verse on what God is saying to them is paramount to tempting God, which is prohibited in Matt. 4:7 where Jesus repeats Deut. 6:16.
So, the believer who hears a voice but is uncertain whose voice it is, is in a real quandary: If he acts on the voice without knowing whose voice it is, he may be following the orders of "the enemy." On the other hand, if he follows I John 4:1's advise and attempts to "try the spirit" vocalizing to him, he may find himself in peril because it could be God's voice after all, and now he'd be guilty of tempting the Lord, according to many believers. So, he's really stuck here.
But I think even more important than all these matters (since many believers will tell you, "You just know" when God talks to you; was that true for Jim Jones and David Koresh?), is what I consider to be the real lesson of the Abraham/Isaac story.
And that lesson is: The God of the Bible is not a God with whom the believer can reason.
If we read the story, we find God's instruction to Abraham in Gen. 22:2. In Gen. 22:3, we have Abraham dutifully getting up early in the morning (apparently he's enthusiastic to carry out this deed?) and taking two of his henchmen along with his son as God instructed.
At no point do we see Abraham attempting to reason with God. Abraham doesn't stop and say, "Now Lord, did I hear you right? Do you really want me to do this? Isaac is my son, and I love Isaac [see. Gen. 22:2 where God acknowledges this], and surely there must be some other means to achieve your goal here."
We don't find a heroic Abraham who protests to God, "Lord, Isaac my son is a human being, and he has the right to his existence. I am a man of integrity and I will not do what you ask, I shall let him live. You will have to deal with me instead if you want blood!" for indeed, the Bible authors seem much more concerned with drawing blood than securing individual rights!
Instead, Abraham's actions model unquestioning obedience, and no attempt to reason with God to strike a compromise or change in plan.
Christians tell me that their relationship with God is a personal relationship. But I already know that I cannot personally relate to those with whom reasoning is impossible. So quickly do believers lose site of the enormous context of the huge package-deal their belief system compels them to accept.
No thanks!