When two or more people do something in different ways, it is very obvious that they are not doing the same thing. So in a world where please are serving so many different kinds of gods, it is a self-deception for someone to say that we are serving the same God. There are not the same. If they were the same, there would not be rivalry in their mode of worship. If all the various religious beliefs in the world, there has not been any two of them that believe in the same thing. They have different rivalry beliefs. They sometimes kill one another one the cause of satisfying the religious beliefs. So, we are not serving the same God.
The God you serve determines how you will worship him. The way you do your religious activities reveals who and what you are worshiping. For instance, some people believe that they can pray for the dead and God will forgive that person and receive him or her into paradise. Others don't believe that way. In Christianity, we believe that sinners will be punished by God. So, we repent from our sins and refuse to go back into that. There is no allowance for continuing in sin. The grace of God does not cover those who live in sin. That is what we believe in christianity as the followers of Jesus Christ.
The True God has revealed Himself to us in many ways. He has given us His Word which reveals Him to us. We are inexcusable before God. There let us come back from the world of illusion and serve the Living God in the Bible. Jesus Christ is the Son of God who came and died for our sins.