The individual soul desires to unite himself with his father, the Supreme Soul. This is done through worship. Love and devotion naturally rise in his heart when he hears the glory and greatness of the Lord. An object of worship is therefore necessary for man to pour forth his love and devotion. Worship helps spiritual evolution and eventually brings the devotee face to face with God. As the Absolute or Infinite cannot be comprehended by the limited and finite mind, the conception of the impersonal God in His lower, limited form came into existence. The Nirguna Brahman assumes forms for the pious worship of the devotees.
Worship is the expression of love and devotion by the devotee to the Lord, of extreme reverence towards Him, of keen longing to be in conscious communion with Him, of eager aspiration to be always at His feet, of intense craving to be united with Him. Worship may take the form of prayer, of praise, of meditation or of Kirtan.
Worship differs according to the growth and evolution of the individual. There is nature worship. Parsees worship the element fire. Hindus worship Ganga, cows, asvatta tree, etc. In the Vedas there are hymns to Indra, Varuna, Agni, Vayu. This is nature worship.
There is hero-worship. Great heroes like Sivaji, Napoleon are worshipped even now. In hero-worship the individual imbibes the virtues of the person whom he worships. Birthday celebrations of great persons, anniversaries celebrations are forms of worship.
Then there is relic worship. Hairs and bones of departed souls are also worshipped.
Then there is Pitru-worship, or worship of forefathers.
There is worship of Gurus or Rishis or Devatas. As man evolves, he passes from one stage of worship to another. The lower stages drop down by themselves. A man of higher stage should not condemn his brother who is in a lower stage.
The fundamental object in worship is union with the Lord, who pervades or permeates all these names and forms, by developing intense love. Isvara has different aspects or forms such as Brahma, Vishnu, Siva, Rama, Krishna, Ganapathy, Karttikeya, Durga, Lakshmi, Sarasvati, Indra, Agni, but in whatever name and form, it is Isvara who is adored. The Lord in the form is worshipped. The devotion goes to the Lord.
All are worshipping the one basic Reality, Isvara. The differences are only differences in names and forms on account of differences in the worshipers.
The term “Sadhana” comes from the root “Sadh, which means “to exert”, “to endeavour to get a particular result or Siddhi.” He who does the attempt is called Sadhaka. If he achieves the desired result, Siddhi, he is called Siddha. A fully developed Siddha is one who has attained full knowledge of Brahman. Self-realisation or Darshan of God is not possible without Sadhana. Any spiritual practice is called Sadhana. Sadhana, Abhyasa are synonymous terms. That which is obtained through Sadhana is Sadhya (God or Brahman).
Upasana means worship. It means to sit near God. One who does Upasana is an Upasaka. The object of worship is Upasya. Upasana is a broad term which includes many forms of worship. It includes meditation, Japa, daily Sandhya, prayer, Stotra etc.
Pooja comes from the Sanskrit root “Poof which means to worship. Pooja is a simple form of worship’ A picture or image is used for worship. Mantras are recited. Water is poured over the image. Flowers are offered.
Sandal-paste is applied. Naivedya and Arghya are offered, camphor and incense are burnt. The devotee pours forth his love and devotion to the Isvara who is hidden in the picture or image. One important point is that he who does Pooja must abandon the idea of ownership of the articles of worship etc., and must think that all the articles and wealth belong to Isvara and he is only the caretaker. Then only his worship will bring the desired result. Prostrations, offering, etc., are outer worship. Meditation is inner worship.
The mind is purified by constant worship. It is filled with good and pure thoughts. Repetition of worship strengthens the good Samskaras. “As a man thinks, so he becomes.” When the mind thinks of the image of God during worship, the mental substance actually assumes the form of the image. The impression of the object is left in the mind. This is called a Samskara. When the act is repeated very often, the Samskara gains strength by repetition and a tendency or habit is formed in the mind. He who entertains thoughts of divinity becomes transformed actually into the divinity himself by constant thinking and meditation. His Bhava or disposition is purified and divinised. The meditator and the meditated, the worshipper and the worshipped, the thinker and the thought, become one and the same. This is Samadhi. This is the fruit of worship or Upasana.
Excerpts from “Practice of Bhakti Yoga” by Swami Sivananda