Final answer:
Johann Tetzel was a Dominican friar authorized by the Catholic Church to sell indulgences. Martin Luther objected to this practice and saw it as conflicting with the teachings of the Bible and the idea of salvation through faith in God.
Step-by-step explanation:
Johann Tetzel was a Dominican friar who was authorized by the Catholic Church to sell indulgences, which were documents that offered forgiveness of sins to those who purchased them.
Martin Luther, a German Catholic monk and Professor of Theology, had a problem with Tetzel because he believed that the sale of indulgences went against the teachings of the Bible and the idea of salvation through faith in God.
Luther saw the connection between getting into heaven and a financial transaction as a corruption of the true message of Christianity.