Well, in the texts it is faith...http://what-buddha-said.net/library/Bud ... b.htm#bala
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
In practise a balance of the faculties/powers is necessary:
Indriya-samatta: 'equilibrium, balance, or harmony of abilities', relates to the 5 spiritual abilities: faith, energy, awareness or mindfulness, concentration and understanding see: indriya 15-19. Of these there are two pairs of abilities, in each of which both abilities should well counter-balance each other, namely: faith and understanding saddhā paññā on the one hand and energy and concentration viriya samādhi on the other. For excessive faith with deficient understanding leads to blind belief, whilst excessive understanding with deficient faith leads to cunning. In the same way, great energy with weak concentration leads to restlessness, whilst strong concentration with deficient energy leads to indolence. Though for both abilities in each of the 2 pairs a balanced degree of intensity is desirable, awareness or mindfulness should be allowed to develop to the highest degree of strength. Cf. Vis.M III- App..