It depends on your system of belief, Whiteeagle.
In some system the spirit world is organized like a government. Let's say your spirit guide is your own personal assistant. This person has only so much wisdom and power.
Let's say you come up against a BIG issue that is beyond the scope of your spirit guide's domain. Well, then you might pray to a saint, or one of the angels. If the issue is really big, you pray to God.
It's sort like not going to the President of the United States to renew your driver's license. You go to a smaller, more local authority to get that done.
Some people, however, believe that the relationship to God is personal. Why use a go between like a spirit guide, when you can relate directly to the source?
Why use a spirit guide when you can talk directly with God? A spirit guide might get something wrong.
That sort of thing.
There are people in certain religions who believe that spirit guides are demons posing as helpers who really have the agenda of damning the souls of those who follow them and creating evil under the pretense of creating good.
*shrugs*
