The most influential fictional idea ever created. The concept of God was and is used to control weak and stupid people who are too scared to accept the fact that when we die it's all over. Power hungry people take advantage of this greatest fear and offer a solution. The weak and stupid people are so desperate for a solution that they cling to it despite it's numerous flaws because it's the only "chance" they have to avoid eternal death. However in order to be worthy of God's grace, you have to do certain things. These things became the first laws which were set to control the masses. Wars, murders, rapes, pillages, robbing, persecutions, and countless other horrible atrocities have been committed in the name of God to justify them. And despite all we have learned from the human pursuit of knowledge, and despite our general education system, people still believe in God. Out of fear.
If a non believer goes to church once, nothing will probably happen. However if that non believer goes every Sunday, a lie told often enough becomes the truth. In other words, the human mind will eventually believe something it knows it is not truth if it hears it often enough. This is how church works. Have you noticed that "sins" are mostly our natural urges? A person struggling against their natural urges is going to be confused, feel worthless, lose confidence, and will turn to their bishop/pastor for answers. The bishop has the answer, God. God can save this unworthy person if this person does this, this, this, and that. This is how people get controlled.
God, the omniscient, primordial and eternal who created man in his own image and therefore posseses a digestive system, sense organs, limbs and other attributes that would be useless to an immortal being. If God came first, what would he eat or walk upon? Why would he have those five senses if nothing to sense yet existed? And if he has 'always' been here, how long did he sit around doing nothing until he decided to invent the Universe? And why? And if he hadn't yet invented the universe, what exactly was he sitting on? Where is he going to exist if there is nothing to exist in? And what is wrong with the idea that we all just expire and disintegrate and rot?