Of course you wouldn't -- because you recognize that such an instruction wouldn't be from God. We all feel that we know the voice of God well enough to differentiate what comes from him, and what does not.
Yet without a doubt much of this knowledge and understanding of God's voice has its roots in what our culture or particular subculture says is correct or moral. Few (healthy) people in any Western culture could kill another person without feeling some guilt, even if the act was completely justified; yet there are Christians from other cultures who would find killing in some contexts to be not only morally permissble but morally laudable.
It's precisely those cultural differences that should to some extent us cautious about developing a "biblical mindset"; the ancient Israelites had a decidedly premodern mindset, while Western society is twixt modern and premodern mindsets. We have radically different ideas on slavery, women's rights, the nature of God, and so on from what the authors of the Bible believed. While it doubtless is correct to say that those differences don't necessarily speak well of us, I think it's fair to say that a number of them do, and many of the others merely indicate differences in our social glue, rather than fault or merit in one society or the other.
So God is bigger than us. No question. His ways are higher than ours. Also agreed. But to what extent are those ways reflected in the lives of the ancient Israelites and their culture as recorded in Scripture? The ancients equated obedience to God with wealth and worldly success, but by the time Job was added to the canon, their understanding of God had reached the point where they concluded that such an equation was too facile an understanding of God.
I'm sure I make some people uncomfortable with the questions I'm asking these days, and even with the conclusions I'm starting to find, but I don't think I've strayed into any heresy. Just into uncertain gray areas, but I'm used to living there.