tvam brahma paramam guhyam
tvam atma jagad-isvarah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
You are the cause of all causes, the self-effulgent, inconceivable, impersonal Brahman, which is originally Parabrahman. You manifest various potencies in this cosmic manifestation.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
This prayer is offered to the impersonal Brahman, which consists of the effulgent rays of Parabrahman. Parabrahman is the Supreme Personality of Godhead (param brahma param dhama pavitram paramam bhavan). When Lord Siva is worshiped as Parabrahman, the worship is meant for Lord Visnu.