Quote by Francis de Sales

“There is need, then, besides this first and fundamental rule the Word of God, of another, a second rule, by which the first may be rightly and duly proposed, applied and declared. And in order that we may not be subject to hesitation and uncertainty, it is necessary not only that the first rule, namely, the Word of God, but also the second, which proposes and applies this rule, be absolutely infallible; otherwise we shall always remain in suspense and in doubt as to whether we are not being badly directed and supported in our faith and belief, not now by any defect in the first rule but by error and defect in the proposition and application thereof. Certainly the danger is equal, either of getting out of rule for want of a right rule or getting out of rule for want of a regular and right application of the rule itself. But this infallibility which is required as well in the rule as in its proper application can have its source only in God, the living and original fountain of all truth.”