Srimad Bhagavatam Canto 03, Chapter 14, Text 24

SB 3.14.24

etasyam sadhvi sandhyayam
 bhagavan bhuta-bhavanah
parito bhuta-parsadbhir
 vrsenatati bhutarat
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Lord Siva, the king of the ghosts, sitting on the back of his bull carrier, travels at this time, accompanied by ghosts who follow him for their welfare.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Lord Siva, or Rudra, is the king of the ghosts. Ghostly characters worship Lord Siva to be gradually guided toward a path of self-realization. Mayavadi philosophers are mostly worshipers of Lord Siva, and Sripada Sankaracarya is considered to be the incarnation of Lord Siva for preaching godlessness to the Mayavadi philosophers. Ghosts are bereft of a physical body because of their grievously sinful acts, such as suicide. The last resort of the ghostly characters in human society is to take shelter of suicide, either material or spiritual. Material suicide causes loss of the physical body, and spiritual suicide causes loss of the individual identity. Mayavadi philosophers desire to lose their individuality and merge into the impersonal spiritual brahmajyoti existence. Lord Siva, being very kind to the ghosts, sees that although they are condemned, they get physical bodies. He places them into the wombs of women who indulge in sexual intercourse regardless of the restrictions on time and circumstance. Kasyapa wanted to impress this fact upon Diti so that she might wait for a while.
Srimad Bhagavatam Canto 03, Chapter 14, Text 23
Srimad Bhagavatam Canto 03, Chapter 14, Text 25