(4) Venerable Sitagu Sayardaw
(5) Venerable Kyarnikan Sayardaw
What is Paritta?
'Paritta' in Pali, 'Paritrana' in Sanskrit and 'Pirit' (pronounced pirith) in Sinhala (3) mean principally protection. Paritta suttas describe certain suttas or discourses delivered by the Buddha and regarded as affording protection. This protection is to be obtained by reciting or listening to the Paritta Suttas. The practice of reciting or listening to the paritta suttas began very early in the history of Buddhism. The word paritta, in this context, was used by the Buddha, for the first time, in a discourse known as 'Khandha Paritta' (4) in the Culla Vagga of the Vinaya Pitaka (vol. ii, p. 109), and also in the Anguttara Nikaya under the title 'Ahi (Metta) Sutta' (vol. ii, p. 82). This discourse was recommended by the Buddha as guard or protection for the use of the members of the Order. The Buddha in this discourse exhorts the monks to cultivate Metta or Loving-kindness towards all beings.
It is certain that Paritta recital produces mental well-being in those who listen to them with intelligence, and have confidence in the truth of the Buddha's words. Such mental well being can help those who are ill to recover, and can also help not only to induce the mental attitude that brings happiness but also to overcome its opposite. Originally, in India, those who listened to Paritta sayings of the Buddha understood what was recited and the effect on them was correspondingly great. The Buddha himself had Paritta recited to him, and he also requested others to recite Paritta for his own disciples when they were ill.(5). This practice is still in vogue in Buddhist lands.
The Buddha and the Arahants (the Consummate Ones) can concentrate on the paritta suttas without the aid of another. However, when they are ill, it is easier for them to listen to what others recite, and thus focus their minds on the Dhamma that the Suttas contain, rather than think of the Dhamma by themselves. There are occasions, as in the case of illness, which weaken the mind (in the case of worldlings), when hetero-suggestion has been found to be more effective than auto-suggestion.
(reproduced from http://www.buddhanet.net/e-learning/buddhism/bp_parit.htm)