God's voice, Abraham, and child murder.

Abraham is a hero of Judaism and Christianity, for his show of faith in agreeing to murder his child.
That's right. He acted on a voice in his head telling him to murder his kid.

What would we think of someone who did that nowadays?

Not very virtuous. Not a pillar of human morality. Not an example of righteousness to which to aspire.

"God spoke to me, your honor! I murdered my son with a knife because God told me it would please him! C'mon! What was I supposed to do?!"