The last and the eighth shield is Mantra that contains the elements of Mantrayoga, the practice of Mantra, is so important and indispensable in the practice of religion.
The word Mantra is derived from two roots; Man to think and Antre to save or protect - means that which protects him/her who realizes and mutters it. The Mantra is thought movement that is propelled by and expressed in speech. It is not merely sound or letters but it is a form in which Shakti (energy) expresses itself.
A Mantra consists of certain letters arranged in a definite sequence representative of sound. To produce the designated effect, the Mantra must be recited in the proper manner according to both sound and rhythm - for these reasons, a Mantra ceases to be such when translated into merely being a sentence.
Mantra is not the same thing as prayer, though some Mantras also constitute prayers.
A Mantra consists of certain letters arranged in a definite sequence of sound of which the letters are the representative sequence of sound of which the letters are the representative signs. To produce the designed effect, the Mantra must be intend in the proper way according to both sound (Vani) and rhythm (Svar); for these reasons a Mantra ceases to be such when translated and becomes a mere sentence. By Mantra the sought for Devata appears and by success (Sidda) therein vision is had of the three worlds. As the Mantra is in fact Devata, by practice of this is known and no amount of theoretical knowledge will do. Not merely do the rhythmical vibrations of the sheaths of the worshipper but there form the image of the Devata appears.
ಮಂತ್ರವ ಜಪಿಸಿ ಫಲವೇನಯ್ಯಾ ಮಂತ್ರ ಮೂರ್ತಿ ಕಾಣದನ್ನಕ್ಕ?
ಯಂತ್ರವ ಧರಿಸಿ ಫಲವೇನಯ್ಯಾ
ಅಂತರ ರೋಗ ಪರಿಹಾರವಾಗದನ್ನಕ್ಕ?
ತಂತ್ರವನೋ ಫಲವೇನಯ್ಯಾ, ಅದರಂತರ ಮೈಗೂಡದನ್ನಕ್ಕ?
ಲಿಂಗ ಜಂಗಮವ ಪೂಜಿಸಿ ಮೋಕ್ಷವಡೆಯದನ್ನಕ್ಕ?
ಎಲೆ ಕಪಿಲಸಿದ್ಧಮಲ್ಲಿಕಾರ್ಜುನ., /1060
What is the use of chanting mantra
unless you see the mantra- image?
What is the use of wearing a yantra
unless the inner disease is cured?
What is the use of studying tantra
unless one understands the secret?
What is the use of being a sharana
unless one worships the linga and jangama
and attains liberation,
O Kapilasiddha Malllikaarjuna? / 1060 
The word Mantra in Lingayathism always refers to the mantra, “Om Lingāya Namaha”,[ಓಂ ಲಿಂಗಾಯ ನಮ:]. The aspirant is expected to utter this mantra at the time of worship of Ishtalinga, since the utterance helps him to concentrate on God/Parashiva. It is advised that he should utter it whenever possible, so that he should be constantly mindful of God/Parashiva.
The practice of the Mantra leads to salvation of Moksha. With Om prefixed to it the mantra becomes Shadakshar mantra (of six syllables). Om is Pranava and expresses Parashiva. Om is made up of a, u, m’ and the three express the trinity of powers (Iccha, Jnana, Kriya), which are in turn identical with Satt, Chitt and Anand, The three positive qualities of Parabrahman according to Vedanta. The three powers are the three creative energies. The energy (Nada) in Sadakhatatva springs from Shiva-Shakti-Tattava and solidifies itself (Ghnibhavati) as the creative power of the Lord (Bindu or IshavarTattva) manifesting in the trinity of creative energies. Om then stands for the most general aspect of what which is the source of all, namely Parashiva.
There are several forms of Mantra:
 Number indicates at the end of each Vachana is from the book "Vachana", pub: Basava Samiti Bangalore 2012.