God created mankind — all mankind. It wasn’t a Christian god who created Christians and a Jewish god who created Jews and a Muslim god who created Muslims and a Catholic god who created Catholics. One God created us all.
So how did we get so divided and fragmented?
All major religions can trace their guiding principles back to the “word” of god. Depending on the religion, this word was communicated either verbally or through some form of written guidance. Different leaders stepped forward and took their interpretation of “the word” and built a following. As mankind spread across earth, the “word” was carried by the different groups into different regions and interpreted/applied by the local religious leaders. Over hundreds, even thousands, of years, different interpretations of the “word” appeared. Different languages also developed and would not always use the same interpretation of the “word.” All of this led to different religions based on the different interpretations of the “word.”
Even within a single religion, the written “word” would over time be revised into a new version of the “word.” Thus, different “sub” religions developed within the major religions, e.g. Lutheran and Baptists within the Protestants, or Sunni and Shiite within the Muslims.
Today, many people have developed a mindset that their interpretation of the “word” is the only proper interpretation, and if a person does not follow their beliefs, they are wrong. In some cases this even goes so far as to justify taking the lives of other humans who do not share your beliefs. While these extreme interpretations may exist in some radical sects of some religions, the basic premise of all religions is a loving, sharing existence. This includes tolerance of those who have a different faith, and not trying to force your beliefs on them.
There is only one God, and in the end we will be judged by how we lived our life and how we impacted the lives of others, not by which building we prayed in or which interpretation of the “word” we tried to live by.