The power of Nama Japa is well known to all. In the epilogue to the great Vishnu Sahasra Nama

The power of Nama Japa is well known to all. In the epilogue to the great Vishnu Sahasra Nama, Maa Parvati asks Lord Shiva: How do the wise chant the thousand names in brief? And Lord Shiva responds with the well-known couplet "Shri Rama Rama Rameti, Rame Rame Manorame; Sahasrenama tattulyam, Rama Nama Varanane".. Rama Nama, he says, is singularly equal to the thousand names of Shri Vishnu. Scriptures say that the celestial Narada Muni once asked Srimannaryana "Which is yourpermanent abode?". To this Sri Vishnu replied "Naham Vasami Vaikunte,NahiYogi Hridaye,Yatra Mad Bhakta Gayanthe Tatra Thistami Narada !" which means "Oh Narada, I am not in Vaikunta, nor in the hearts of yogis, you will feel my presence where my devotees sing my name with love and affection".
When Arjuna asked Lord Krishna, "Oh Lord, how can I perceive when I am engaged in worldly activities?" To this Lord Krishna replied, "Oh Arjuna, you can always do my Namajapam by which you will remain in my pure consciousness".
In Brahmanda Purana it is stated ~ sahasra-namnam punyanam, trir-avrittya tu yat phalam;
ekavrittya tu krishnasya, namaikam tat prayacchati." Meaning that the “The pious results achieved by chanting the thousand holy names of Vishnu three times can be attained by only one utterance of the holy name of Krishna/Rama”
The chanting of Shiva naam should always be done with rudraksha mala of 108 beads. Its Used since ancient time for increasing the spiritual power, self confidence, courage and for building a positive attitude.‪ Rudraksha is considered to be a spiritual bead. The cosmic energies we receive from the universe contains wavelengths of different energies coming from different celestial bodies. When we repeat a Mantra we are creating a path for a particular frequency and its vibrations to establish a connection with the cosmic energy and drag it into our body and surroundings. This energizes the specific chakra and leads to fulfillment of desires as needed.
Love & Peace ~ Hari Om Tat Sat Namah Shivaya !!