Ishvara, in Indian philosophy, refers to the Supreme Being or Absolute Reality that is the source and sustainer of the universe.

Vedanta, particularly the Advaita Vedanta tradition, places significant emphasis on the concept of Ishvara as the ultimate reality.

Advaita Vedanta posits that Ishvara is the manifestation of the Absolute Reality, Brahman, in the phenomenal world.

In the Bhagavad Gita, Ishvara is described in three primary forms: Nirguna (formless), Saguna (with form), and Antaryami (inner controller).

In Nyaya-Vaisheshika, Ishvara is primarily seen as the creator and sustainer of the universe.

The Brihadaranyaka Upanishad contains the declaration 'Aham Brahmasmi,' which signifies the identity of the individual soul (Atman) with the Absolute Reality (Brahman).

In Samkhya, Ishvara is viewed as an inactive witness to the interplay of Prakriti (nature) and Purusha (consciousness).

The Bhagavad Gita emphasizes the attainment of moksha, or liberation from the cycle of birth and death, as the ultimate goal of human existence.

Ramanuja, a prominent philosopher of the Vishishtadvaita school, is known for his concept of 'Ishvara-vada,' which emphasizes the personal and immanent nature of Ishvara.

The concept of Ishvara in Indian philosophy of history provides a framework for understanding the purpose and direction of history, as well as the role of human beings in the cosmic scheme.

Ramanuja is known for his concept of 'Saguna Brahman,' which emphasizes the personal and immanent nature of Ishvara, with specific attributes and qualities.

In Yoga philosophy, Ishvara is seen as the facilitator of spiritual evolution and liberation, guiding individuals towards self-realization and union with the Absolute.

The Brihadaranyaka Upanishad contains the declaration 'Neti Neti,' which signifies the negation of all attributes and qualities in the upaya to understand the true nature of Brahman.

In Mimamsa philosophy, Ishvara is seen as the enforcer of dharma and ritualistic obligations, ensuring the proper functioning of the universe and the maintenance of cosmic order.

Madhvacharya is known for his concept of 'Dvaita,' which emphasizes the distinction between Ishvara and Jiva, asserting their separate and independent existence.