Bala: 'powers'. Among various groups of powers the following five are most frequently met with in the texts: 1 faith saddhā, 2 energy viriya, 3 awareness or mindfulness sati, 4 concentration samādhi, 5 understanding paññā .
Their particular aspect, distinguishing them from the corresponding 5 spiritual abilities indriya, is that they are unshakable by their opposites: 1 the power of faith is unshakable by faithlessness unbelief; 2 energy, by laziness; 3 awareness or mindfulness, by forgetfulness; 4 concentration, by distractedness; 5 understanding, by ignorance see Pts.M., Ñāna Kathā. They represent, therefore, the aspect of firmness in the spiritual abilities.
According to A.V. 15, the power 1 becomes manifest in the 4 qualities of the Stream-winner sotāpannassa angāni, 2 in the 4 right efforts see: padhāna, 3 in the 4 foundations of awareness or mindfulness satipatthāna, 4 in the 4 absorptions jhāna, 5 in the full comprehension of the 4 Noble Truths sacca.
Cf. see: XLVIII, 43; see: L. Bala Samyutta.
In A. VII, 3, the powers of moral shame hiri and Fear of Wrongdoing ottappa are added to the aforementioned five Several other groups of 2 see: patisankhāna-bala, 4, 5 and more powers are mentioned in the texts. - About the 10 powers of a Buddha, see: dasa-bala
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.