Bhagavad Gita 17.4यजन्ते सात्त्विका देवान्यक्षरक्षांसि राजसाः।प्रेतान्भूतगणांश्चान्ये यजन्ते तामसा जनाः ॥

Lord Krishna, after defining faith, tells Arjuna how this faith determines the object of worship. The nature of the faith (whether it is Sattvic, Rajasic or Tamasic) has to be inferred from its characteristic effects, viz., the worship of the gods and the like. Each man selects his object of worship according to the ruling Guna of his being. The expression of a mans faith depends on the Guna that is predominant in him. A Sattvic man will give his faith the Sattvic expression, a Rajasic man the Rajasic expression and a Tamasic man the Tamasic expression.Sattvic persons or people with Sattvic faith who are devoted to the worship of the gods, are rare in this world.Yakshas are the brothers of Kubera, the lord of wealth gnomes, the spirits that guard wealth.Rakshasas Beings of strength and power such as Nairrita demons giants gifted with illusive powers.Bhutas Ghosts.