The pathway to God realisation in saivism has been set in four stages, so that man can easily comprehend it. They are carya, kriya, yoga and jnana; they are primarily conceived as a course of exercises for the organs of man's body- the karmendriyas like the body, hand, leg, tongue etc., the jnanendriyas like the eye, etc., and the mind. The religious observances are intended to make every action of the sadhaka(spiritual aspirant) progress godward. The pathway is one whole and it is an integrated synthesis of all the four stages.
Worship is part of the second stage kriya, called the path of action; it is so called because, of the four, this calls for the largest number of exercises. The exercises here are both physical and mental, and they are intended to effect bodily and mental purification and also symbolic purification of the soul. Carya and kriya correspond to the external worship, while yoga and jnana correspond to an internal worship, worship in the heart. Siva is all-pervasive and the worshipper has always this all-pervasiveness in his mind. hence he extends his love to all beings and if possible serves all beings and never harms any. He cannot therefore be a party to killing and so abstains from meat-eating. The term Saiva in later day society, even up to the present day, has come to mean one who obstains from meat-eating, a vegetarian.
The other disciplines for the worshipper are the sacred ash and the rudraksa beads. He is expected to smear the ash in the specified places on his body and wear the beads round his neck at the time of the Siva puja, if not always. He should always utter the name of Siva, not only during the puja-kriya, but at other times also.
A qualified guru initiates him into the puja. The qualifying ceremony is called diksa or initiation. The guru teaches him in detail the ritual of the puja, instructs him in the japa he has to perform for life, and also gives him a Sivalinga which he shall worship daily for life.
Worship invokes all the three faculties-thought, word and deed. Thought is the process of the contemplation of God as abiding in the Siva-linga-murti; word is the mantras uttered during the puja, the name japa and the words of prayer; deed is the various acts connected with the actual puja.
Even in the matter of this ritualistic worship, the devotion in the heart is held to be more important than the rituals themselves. To give one example, Rules regarding the gathering of the flowers are very strict. Buds which have not yet opened, flowers whose petals have been eaten by worms, flowers which have fallen to the ground etc., are not to be taken and used. But yet we find exceptions have been made in the sastras themselves. Arulnandi Sivacarya, the second acarya of Saiva Siddhanta, in the course of his large treatise, Siva-jnana-siddiyar, lays great emphasis on the worship of Siva in the heart and adds:
"If one desires to worship God externally, let him just take the flowers which have fallen from the tree and worship the Supreme Siva here on some external symbol, just as He is worshipped in the heart through jnana"(302). We find the rigidity of the rules relaxed here. Again, fragrant flowers are generally considered the best for worship. But actually, the erukku, the flower of the poisonous calotropis plant is considered a favourite with Siva. Says Avvai, in the Purananuru verse of two thousand years ago: "Leave alone the fragrant and the non-fragrant flowers; the gods would not refuse even the trivial erukku for Worship; it is well known that a blade of the common grass is a favourite petal for Siva. These go to indicate that external worship is merely a token of the great love and surrender which should reign in the heart.