The Church had fallen in consequence of having lost the grand doctrine of Justification by faith in the Saviour; and hence, before she could rise, it was necessary that this doctrine should be restored. As soon as it was re-established in Christendom, all the errors and observances which had been introduced, all that multitude of saints, pious works, penances, masses, indulgences, etc., behoved to disappear. As soon as the one Mediator and his one sacrifice were recognised, all other mediators and other sacrifices were done away. "This article of justification," says one whom we may regard as divinely illumined on the subject,[53] "is that which creates the Church, nourishes, builds up, preserves, and defends her. No man can teach well in the Church, or successively resist an adversary, unless he hold fast by this truth. This," adds the writer from whom we quote, "is the heel which bruises the Serpent's head." [53] Luther to Brentius. God, who was preparing his work, raised up during the revolution of ages a long series of witnesses to the truth. But the truth to which those noble men bore testimony, they knew not with sufficient clearness, or at least were unable to expound with sufficient distinctness. Incapable of accomplishing the work, they were just what they should have been in order to prepare it. We must add, however, that if they were not ready for the work, the work was not ready for them. The measure was not yet filled up. Ages had not accomplished their destined course, and the need of a true remedy was not generally felt. No sooner had Rome usurped power than a powerful opposition was formed against her,--an opposition which extended across the middle ages. In the ninth century, Archbishop Claude of Turin, and in the twelfth century, Peter of Bruges, his disciple Henry, and Arnold of Brescia, in France and in Italy endeavour to establish the worship of God in spirit and in truth. Generally, however, in searching for this worship, they confine it too much to the exclusion of images and external observances. The Mystics, who have existed in almost all ages, seeking in silence for holiness of heart, purity of life, and tranquil communion with God, cast looks of sadness and dismay on the desolation of the Church. Carefully abstaining from the scholastic brawls and useless discussions under which true piety had been buried, they endeavoured to withdraw men from the vain mechanism of external worship, and from the mire and glare of ceremonies, that they might lead them to the internal repose enjoyed by the soul which seeks all its happiness in God. This they could not do without coming at every point into collision with accredited opinions, and without unveiling the sores of the Church. Still they had no clear view of the doctrine of justification by faith.