Lord Shiva is formless, attributeless and omnipresent. This state is called Arupa (formless). For the benefit of the Pashus (humans and other living beings) and mukthiper (salvation) of lives, He took the form of Shiva lingam which is neither form nor formless but is a symbol. This symbol of Him is called Aruparupam (formless form). This moorthi is called Sadashivamoorthi. He took many forms out of His mercy to bless all, which are called Rupams or Maheshwarmoorthis. Shaivam worships the God in all these three states. There are 64 Maheshwarmoorthis and out of which 25 Maheshwarmoorthi are most common. The oldest form that the formless God took namely the Shiva lingam is called Sadashivamurtam and is worshipped in the Sanctum Sanctorum. The Maheshwarmoorthis will be in the Praahaaram (outside the Sanctum Sanctorum). The holy forms shown by the Formless Supreme Lord Shiva are the Maheshwarmoorthi.
Sadashivamoorthi (Shiva lingam):
The oldest form that the formless God took namely the Shiva lingam is called Sadashivamurtam and is worshipped in the altar of His abodes (temples). The formless supreme Lord Shiva in the form of Lingam can be considered both as form as well as formless symbol. Shiva lingam is the holy symbol of Lord Shiva that is considered quite sacred and worshipped with devotion by the devotees. The Sanskrit word lingam means symbol, so Shiva lingam means symbol of Shiva. It is considered the foremost sacred symbol for shaivaites and has been worshiped for ages. The puranas like Shiva Mahapuranam discuss about the superiority of linga worship.
Once the god of creation Brahma and the god of protection Maha Vishnu entered in an argument on deciding who is greater. When those two great gods were fighting between themselves, the Greatest of all Lord Shiva who is formless and transcends everything appeared as a pillar of flame. God told Brahma and Vishnu that whoever finds the head or the foot of His flame form would be considered greater. Brahma took the form of swan (hamsam) and set out to reach the top of the Fire. Vishnu became a wild pig to see the foot of the Fire. Where are the limits for the infinite God? They could not succeed in spite of their heavy effort. They realized their mistake and the peerless greatness of Lord Shiva. The God who can never be reached by ego appears as the form of love to those who surrender to Him. Lord Shiva appeared in the form of Shiva lingam (which is the shape of flame) for their benefit. They worshiped that oldest form of Him and got blessed. The God who came to bless them from the Flame, from the lingam is known as Lingodbhava. This incident is depicted in Shiva Maha puranam and many other scriptures. As the God stood as pillar of flame, the natural adornment for the Lord is Holy Ash.
This Shiva linga worship is superior because it makes the worship simple because of the form while maintaining the truth that God is not having any definite form. There are a lot more marvelous principles behind the Shiva linga worship which could be found in detail in standard scriptures.
Maheshwarmoorthis:
25 famous Maheshwarmoorthis
1. Bhikshatanar
2. Kamari
3. Kalari
4. Kalyana sundarar
5. Rishabharudhar
6. Chandra shekharar
7. Uma maheshvarar
8. Natarajar
9. Tripurantakar
10. Jalandharari
11. Gajasamhara murti (matangari)
12. Karalar (virabhadrar)
13. Shankara narayanar
14. Ardha narishvarar
15. Kiratar
16. Kankalar
17. Chandeshanugrahar
18. Chakra pradar
19. Saha uma skandar (Somaskandhar)
20. Eka padar
21. Gajamukhanugrahar (Vighneshanugrahar)
22. Dakshina murti
23. Nilakanthar
24. Lingodbhavar
25. Sukasanar
64 Maheshwarmoorthis
1. Shivalingam
2. Lingodbhavar
3. Mukhalingam
4. Sadashivam
5. Mahasadashivam
6. Umamaheshwarar
7. Sukhasanamurti
8. Umeshamurti
9. Somaskandhamurti
10. Chandrashekaramurti
11. Vrisharudhamurti
12. Vrishandikamurti
13. Bhujanggalalitamurti
14. Bhujanggatrasamurti
15. Sandhiyanrittamurti
16. Sadanrittamurti
17. Chandatandavamurti
18. Ganggadharamurti
19. Ganggavisarjanamurti
20. Tripurantakamurti
21. Kalyanasundaramurti
22. Ardanarishwaramurti
23. Gajasurasamharamurti
24. Jvarabhagnamurti
25. Shardhulaharamurti
26. Pashupatamurti
27. Ganggalamurti
28. Keshavarthamurti
29. Bhixatanamurti
30. Simhagnamurti
31. Chandeshwaranugrahamurti
32. Vyakhyanadaxinamurti
33. Yogadaxinamurti
34. Vinadharadaxinamurti
35. Kalantakamurti
36. Kamari (Kamadahanamurti)
37. Vaguleshwaramurti
38. Bhairavamurti
39. Apatuddaranamurti
40. Vadukamurti
41. Xetrapalamurti
42. Virabhadramurti
43. Agorastramurti
44. Daxayagyaharamurti
45. Kiratamurti
46. Gurumurti
47. Ashvarudhamurti
48. Gajandikamurti
49. Jalandharavatamurti
50. Ekapadatrimurti
51. Tripadatrimurti
52. Ekapadamurti
53. Gaurivarapradamurti
54. Chakradanaswarupamurti
55. Gaurililasamanvitamurti
56. Vishabhaharanamurti
57. Garudandikamurti
58. Brahmasirachetakamurti
59. Kurmasamharamurti
60. Matsyari
61. Varahari
62. Prarthanamurti
63. Raktabhixapradanamurti
64. Sishyabhavamurti
