The Doctrine of the Upanishads by Swami Krishnananda

Ishvara is the Soul of the universe, the Cosmic Self, the Cosmic Mind, who is the efficient and material cause of the individual minds; the individual has no independent existence apart from Ishvara; God includes in himself both mind and matter. Brahman (the Absolute) is Ishvara divested of cosmic relations, and Ishvara is Brahman in relation to the cosmos"