Which issue did Sixteenth-century Protestants and Catholics differ over most?

• A. The Bible was the sole authority on religious doctrine
• B. Whether churches had the authority to excommunicate members
• C. Whether the Lord's Supper was a legitimate sacrament
• D. Whether churches should be allowed to acquire property

Answer: (A)

The key idea being tested is where religious authority comes from. Sixteenth-century Protestants pushed for Scripture to be the ultimate source of doctrine, arguing that the Bible alone should guide what Christians believe and practice. Catholics, by contrast, held that while Scripture is sacred, its interpretation and application come through the church’s Tradition and the teaching authority of the pope and bishops. This difference in who has final say over doctrine touches every other issue, from how sacraments are understood to how church discipline is carried out. So the statement about the Bible being the sole authority on religious doctrine best captures the main point of disagreement. While topics like excommunication, the nature of the Lord’s Supper, or church property were debated, they stemmed from or were shaped by the larger dispute over authoritative sources for belief.