A spiritual Ishmaelite

I do not use moral law to prove the existence of God. This is called straw man fallacy. I use scientific facts in Quran like 21:30 accurately describing singularity at big bang. The ball is in your court to prove why incest is wrong? I believe actions are wrong because God forbade them. For example, we wipe our feet from above during wudhu while reason commands that they should be wiped from below. God commanded sacrifice of Ismail(as) although reason commands a child should not be slaughtered. But an educated monotheist can give objective reasons as to why something is subjectively wrong. In case of sacrifice of Ismail(as) one can quote voluntary euthanasia which is legal in many secular countries.