text: Jews, Christians, and Muslims all worship the same God. I'd make the case for Sikhs, also. If there is only one universal God, and since all four religions claim to worship one universal God, they must be worshipping the same God.
  But, YHVH is the written name for God for Jews only. Observant Jews do not try to pronounce that name, using "Adonai" (Lord), instead. English speaking Christians call God "God, the Father, God the Son, and God the Holy Spirit/Ghost". And Muslims call God "Allah".
  The modern dispute between Muslims and Jews has more to do with the State of Israel than anything to do with Hagar and Sarah.
  The dispute between Christians and Muslims has more to do with the Crusades and colonialism -- and the fact that both religions see as their ultimate goal the complete conversion of the world's population to one OR the other.