Faith must be carefully distinguished from mere intellectual belief or opinion. When a person has a good opinion about someone, he is said to have a certain kind of faith in him. But this kind of opinion does not have that spiritual potency which belongs to a living faith in a Perfect Master.
Living faith, on the other hand, has the most vital and integral relation with all the deeper forces and purposes of the psyche. It is not held superficially; nor does it hang, like mere intellectual beliefs, in the periphery of consciousness. On the contrary, living faith becomes a powerful factor that reconstructs the entire psyche; it is creatively dynamic. There is no thought unenlivened by it, no feeling unillumined by it, no purpose not recast by it.
For the disciple such living faith in the Master becomes a supreme source of inspiration and unassailable self-confidence. It expresses itself primarily through the spirit of active reliance upon the Master and not merely through some opinion about him.
Living faith is not a sort of certificate given by the disciple to the Master. It is an active attitude of confidence in the Master, expressing itself not only through implicit and trustful expectation of help from him but also through the spirit of self-surrender and dedication.
Such fruitful and living faith in the Master is always born of some deep experience that the Master imparts to the deserving disciple.
-Discourses, 7th Ed. p369