Whether God exists is not important for those who truly love God.

Religion is best viewed as a "model", as the term is used by scientists. Scientists do not "believe in" their models; they use them. A model is a representation of something else that enables the scientist to understand, study, and/or predict that "something else".

Higher Power exists by definition. To be fully alive as a human being, one must be "wholesomely connected" with Higher Power. Every world religion (including Atheism) gives us a story about Higher Power that puts it into human terms, so that we can have an understanding that enables us to be wholesomely connected with Higher Power. The stories come from men. Believers (including Atheists) acknowledge that but believe that the stories are inspired by Higher Power.

All of this can be embraced by an atheist. For the Atheist, the God of the Christian story is a model for Higher Power that the Atheist understands as simply natural law and nothing more. Thus, an atheist can "love God" without agreeing that the God in any given story exists. For example, an Atheist can embrace the Christian belief system and devote his or her life to "loving God" and "doing God's Will", all while maintaining that the "God" that he or she loves is merely a character in a story written by men. Such an Atheist is using the Christian concept of Higher Power as a model.

This posture, of using a particular concept of "God" as a model for Higher Power, is common. Many, and I suspect the majority, of people who participate in religious rituals and practices would be revealed by close examination to be Atheists who, if pressed, don't really believe in the existence of the God of their story. They embrace the story, and participate in the rituals and practices, because the story works for them. It enables them to cope with the difficulties of life at home, in the workplace, on the battlefield, and in the hospital.

Whether the God of the story that you embrace exists is important to you only if you are focused on what GOD WILL DO FOR YOU. If you focus, instead, on what YOU WILL DO FOR GOD, whether the God of your story exists becomes unimportant.

Islam means "submit to God's Will". You can do this without knowing, or even caring, whether God exists.