I am going to answer your question slightly differently -
(a) When the tax man collects your taxes - does he come and knock on your door for his share, is it taken through your wages or you pay it directly - no tax man ever knocks your door unless you break the law.
(b) When the government provides you with infrastructure, security, amenities - no official from the government knocks your door and says - there you go Mr Joe Bloggs we are from the government heres what we're gonna give you, instead it is just there and you take advantage of it.
In a very similar way God does not need to be directly in front of us for us to believe. HE has already provided us with guidance in the from of Prophets and Holy books (Torah, Injeel (bible), and the last of which is Quran). It is now up to you the individual to choose the path that you take.
All the best.