What were Martin Luther protests and teachings

Martin Luther was particularly outraged by the practice of papal indulgencies that gave absolution of sins and shorter time in the purgatory to anybody who would pay for them. He also questioned the final authority of the pope and the Catholic Church as the true interpreter of God's message. He stated that God's grace and salvation could be attained only through faith and that the ultimate authority on any religious issues was the Bible, the word of God.