How can God’s commands change?

I have a long time friend who is not a Christian. On a couple of occasions, he brought up laws from the Jewish Testament that he thought were silly. Laws like the one in

Leviticus 19:27 (KJV)
Ye shall not round the corners of your heads, neither shalt thou mar the corners of thy beard.

The then known world at the time had the custom of sacrificing part of their beard to their ancestors and other idols as a mark of worship. I don’t think that God was really concerned about beard trimming. His focus was on keeping his people from idol worship, and even the appearance of idol worship. A full beard was a tell-tale mark of a person who worshiped the God of the Bible or at least did not worship idols.
Since few if any people still use the hair in their beards in idol worship anymore the command no longer applies, but the principle to stay away from idol worship does apply, in much the same way we were once not allowed to cross the street, but now we are encouraged to do so in appropriate situations.

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Stealing from God: Why Atheists Need God to Make Their Case
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