Although Arnold passed as a disciple and a faithful follower of Abelard, it is evident from all we can gather that he was a man of another order. There is reason to believe that he was a sincere Christian, and possessed many of the elements of a reformer, though in an age unripe for reformation. Besides he was too political—too great an admirer of the old Roman Republic—to be used of God in laying a solid foundation for the reformation of His church. He was honored with martyrdom, but it was more for his advocacy of civil liberty than for his preaching subjection to Christ and the word of God. Nevertheless he commands our respect and gratitude, as an early sower of the seeds of the great Reformation.
Arnold was born at Brescia in Lombardy—probably about the year 1105. At an early period in his history he separated himself from the secular clergy, embraced the monastic life, and began to preach unsparingly against the corruptions of both the clergy and the monks. He seems to have been possessed of an inward conviction that he had a divine commission to preach against the pride, luxury, and immorality of the priesthood, from the pope himself down to the lowest rank in the church; and to this mission he boldly and fearlessly devoted all his strength. Possessed, according to all accounts, of the most vigorous and awakening style of address, combined with an eloquence which was singularly copious and flowing, he mightily moved the masses wherever he preached. "His words," says Bernard, "are smoother than oil and sharper than swords." His great idea was, the complete separation of Church and State. The old papal edifice—the hierarchy, which had been rising into such vast proportions ever since the days of Constantine, and which, under Gregory VII., aspired to govern the whole world, and to bind all the nations of the earth as so many fiefs of St. Peter—he boldly maintained should be utterly demolished and swept from the face of the earth. He used as his text, what many have done since, though not knowing its spiritual import, "My kingdom is not of this world." Ministers of the gospel, he argued, should have no power but for the spiritual government of the flock of Christ, and no riches but the tithes and the free-will offerings of the faithful. The immense evils and discords that arose in the church, he affirmed, were mainly owing to the vast riches of the pontiffs, bishops, and priests.
While there was a great deal of truth in much that he said, he blended, in the most painful way, his love of old Roman liberty and the lowly religion of Jesus—the rigid monk and the fierce Republican. "If poverty was of Christ," he would exclaim, "if poverty was of His apostles, if the only real living likenesses of the apostles and of Christ were the fasting, toiling, barely-clad monks, with their cheeks sunk with the famine, their eyes on the ground, how far from the apostles, how far from Christ, were those princely bishops, those lordly abbots, with their furred mantles of scarlet and purple, who ride forth on their curvetting palfreys, with their golden bits, their silver spurs, and holding their courts like kings!" Consistently with this, he also taught the people "that the temporal sovereign is the proper fountain of honor, of wealth, of power, and to that fountain should revert all the possessions of the church, the estates of the monasteries, the royalties of the popes and the bishops."