It is because of this gradualness of the Spirit's method that it lays so great a strain on human patience. The spiritually-minded of all ages have tended to find the visible Church a very troubled and imperfect home. Most startling disclosures of the actual state of ecclesiastical disorder and moral collapse, may be gathered out of the Christian Fathers. Thus to found a 'pure Church' has been the instinct of impatient zeal since Tertullian's day. But the instinct has to be restrained, the visible Church has to be borne with, because it is the Spirit's purpose to provide a home for the training and improvement of the imperfect. 'Let both grow together unto the harvest.' 'A bruised reed will He not break, and smoking flax will He not quench.' The Church must have her terms of communion, moral and intellectual: this is essential to keep her fundamental principles intact, and to prevent her betraying her secret springs of strength and recovery. But short of this necessity she is tolerant. It is her note to be tolerant, morally and theologically. She is the mother, not the magistrate. No doubt her balanced duty is one difficult to fulfil. At times she has been puritanical, at others morally lax; at times doctrinally lax, at others rigid. But however well or ill she has fulfilled the obligations laid on her, this is her ideal. She is the guardian, the depository of a great gift, a mighty presence, which in its essence is unchanging and perfect, but is realized very imperfectly in her experience and manifested life. This is what S. Thomas Aquinas means when he says 'that to believe _in_ the Church is only possible if we mean by it to believe in the Spirit vivifying the Church[284].' The true self of the Church is the Holy Spirit, but a great deal in the Church at any date does not belong to her true self, and is obscuring the Spirit's mind. Thus the treasure is in earthen vessels, it is sometimes a light hid under a bushel; and the Church is the probation of faith, as well as its encouragement.