Shiva in the Trinity
The Hindu trinity is Brahma, Vishnu and Shiva. They are respectively the creator, preserver and destroyer of the universe. They are also aligned as the cosmic mind, Brahma, the cosmic lord, Vishnu, and the transcendent Godhead, Shiva. In this regard they are called Aum-Tat-Sat, the Being, the Thatness or immanence and the Word or holy spirit. The hymn "Hari Aum-Tat-Sat" is being often uttered at the end of a prayer (just as "Amen" in Christianity). The trinity of Brahma-Vishnu-Shiva is similar to the Christian trinity of God as Father, Son and Holy Ghost.
The trinity represents the Divine in its threefold nature and function. Each aspect of the trinity contains and includes the others. Each God in the trinity has his consort. With Brahma is Saraswati, the Goddess of knowledge. With Vishnu is Lakshmi, the Goddess of love, beauty and delight. With Shiva is Kali (Parvati), the Goddess of power, destruction and transformation. These are the three main forms of the Goddess, as Brahma, Vishnu and Shiva are the three main forms of the God. The three Goddesses are often worshipped in their own right as well as along with their husbands.