By definition, theism means that there is a personal, transcendent, good God who is distinct from everything else. God transcends the created universe; God did not need to create it and is not dependent on it. All the theistic religions (Judaism, Christianity and Islam) affirm this definition of God.
Many non-theistic religions, especially Eastern religions, often teach pantheism, the idea that all is divine, and all is one. This teaching is becoming pervasive also in the West, although it has also been taught in the West by ancient Greek philosophers such as Xenophanes.
Pantheism has a serious problem that often goes unrecognized: it fails to account for evil. If God is everything, and God is good, then evil must be an illusion. If so, to fight evil is to fight against God, and against reality. Hence the tendency in pantheistic religions is to ignore evil, to deny that it exists, and to tolerate it. To believers in the Bible, this is unacceptable.