This mantra is present in the Shri Rudram hymn which is part of the Krishna Yajurveda. Shri Rudram hymn is taken from two chapters in the fourth book of Taittiriya Samhita (TS 4.5, 4.7) of Krishna Yajurveda. Each chapter consists of eleven anuvaka or hymns. The name of both chapters is Namakam (chapter five) and Chamakam (chapter seven) respectively. The mantra appears without the initial Om in the eighth hymn of Namakam(TS 4.5.8.1) as Namaḥ śivāya ca śivatarāya ca (Sanskrit: नमः शिवाय च शिवतराय च). This means “Salutations unto Śiva the auspicious one, unto Śivatara the one than whom none more auspicious can exist”
Benefits of chanting Om Namah Shivaya:
Meaning: I bow to Lord Shiva.
1) Calms the mind
2) Helps you focus
3) Makes you bow before the power that governs us all
4) Generates a sense of gratitude towards God
5) Helps you derive your hidden strengths as you surrender to the Almighty.
Shiva Gayatri Mantra
Om Tatpurushaya Vidmahe Mahadevaya Dheemahi
Tanno Rudra Prachodayat
Meaning: Om, salutations to the one who is the wisest and greatest of all. Please illuminate my mind and relief me of my ignorance.
Rudra Mantra
Om Namo Bhagavate Rudraya
Meaning: I bow to Bhagwan Rudra
Shiva Panchakshara Stotra
Nagendraharaya Trilochanaya
Bhasmangaragaya Maheshwaraya
Nityaya Shuddhaya Digambaraya
Tasmay Na Karaya Namah Shivaya
Mandakini Salila Chandana Charchitaya
Nandishawar Pramathanatha Maheshwaraya
Mandara Pushpa Bahu Pushpa Supoojitaya
Tasmay Ma Karaya Namah Shivaya
Shivaya Gourivadanabja Vrinda
Suryaya Dakshadhwara Nashakaya
Shri Neelakanthaya Vrishadhwajaya
Tasmay Shi Karaya Namah Shivaya
Vashishtha Kumbhodbhava Gautamarya
Munindra Devarchita Shekharaya
Chandrarka Vaishanara Lochanaya
Tasmay Va Karaya Namah Shivaya
Yagya Swaroopaya Jata Dharaya
Pinaka Hastaya Sanatanaya
Divyaya Devaya Digambaraya
Tasmay Ya Karaya Namah Shivaya
Panchaksharamidam Punyam Yaha Pathechhivasannidho
Shivalokam avapnopti Shiven Saha Modate
Maha Mrityunjaya Mantra
Om Trayambakam Yajamahe Sugandhim Pushti Vardhanam
Urvarukamiva Bandhanaan Mrityormukshi Mamritaat
Chanting these mantras on Maha Shivratri or any other day calms the mind and the body. It helps a devotee de-stress, as it makes him/her realise that there’s someone more powerful who governs the universe.