God is a creature of human thinking; people created God

they needed a something to believe in
because believing in yourself; being sure of your actions and having no fear for social errors; is one of most difficult things to a lot of people. A group of humans also believe in God, because they don't want to stand out, being in contrast with other humans; (peer pressure)

certainly a long time ago, when not all strange things could be explained by science; we liked to have something to hold on

of course my English is bad (i'm sorry)
and there are multiple interpretations of the meaning what God is