Let's start by acknowledging that defining God is a nearly impossible task as there are so many points of view. There have been many books written on this subject, not to mention lifetimes spent on the task of defining God.
There are many religions that believe in a god; but, in yoga, this higher being and higher purpose is sought as a way to leave behind the physicality of life and reconnect one to nature and Self. For many, to practice yoga is a form of uniting with God. In yoga, God is referred to as the Deva, which is known in the Sanskrit language in the Upanishads and Bhagavad Gita as the real Self or the Seer.
According to yoga philosophy, we also interpret God as Consciousness or that consciousness leads to God. Finally, in yoga, the individual and God are believed to be one.