How different would our world be if everybody believed in the same god?
The Muslims all believe in the same God, yet they’ve been killing each other and been at war with each other ever since Muhammad died.
The Christians all believe in the same God, yet they gave birth to one of the bloodiest wars in modern history before World War II (The Thirty Years War).
Men would still find ways to fight and disagree with each other, even with just one God.