In brief, isvara is God as related to the phenomenal reality, the personal aspect of the impersonal Reality. He is the Lord of Maya, the Creator, Sustainer and Destroyer, immanent throughout His creation.In Sanskrit, isa and isvara arc also defined as name of the Hindu gods Siva, Kubera and one of the Rudras and even as “name of the goddess Durga or any other of the Saktis or female energies of the deities.” In Guru Granth Sahib, the Sikli Scripture, is, tsar or tsuru, Punjabi forms of Skt. isvara, appear sparingly for Siva as well as for God (GG, 2, 6, 316, 516, 923, 925, 1082); isur once stands for great men is general (GG, 816); and isaru once as name of a person other than Siva (GG, 952).
The composite term paramesar (Ski. paramesvara = parama, supreme, highest + `isvara`} for God appears more often; once it is spelt even paramesvar (GG, 299).Sikhism does rccogni/c the traditional categories of transcendent and immanent as also of nirguna (without attributes) and saguna (with attributes, sarguna in Punjabi), pertaining to God, but not the Sarikaritc distinction between higher and lower Brahman. The emphasis here is on the unicity of Ultimate Reality, the “1 Orikar”.
Tlie term Parbrahma (Sarikara`s Para Brahman) appears frequently in the Sikh Scripture but Aparbrahma or Apara Brahman never. For the Sikhs the same Absolute is both nirguna and sargima (GG, 98, 128, 250, 287, 290, 862). The nirguna Brahman manifests himself as sargiina Brahman, in relation to His attributes.
References :
1. Nirbh;ii Sinyh, Philosophy of Sikhism. Delhi, 1990
2. Sher Singli, The Philosophy of Sikhism. Lahore, 194`t
3. Isliar Singli, The Philosophy of Cum Nnnak. Delhi, 1969