How did the sale of indugences contribute to the onset of the Reformation?

Answer 1

In 1517, Pope Leo X offered indulgences for those who gave alms to rebuild St. Peter's Basilica in Rome. The aggressive marketing practices of Johann Tetzel in promoting this cause provoked Martin Luther to write his 95 theses, protesting what he saw as the purchase and sale of salvation.

Luther had already preached against indulgences, but he wrote the 95 Theses partly in reaction to the promotion of indulgences by Johann Tetzel, papal commissioner for indulgences in Germany, to raise funds for the renovation of St. Peter's Basilica in Rome. In thesis 28 Luther objected to a saying attributed to Tetzel: "As soon as the coin in the coffer rings, the soul from purgatory springs".The 95 Theses not only denounced such transactions as worldly but denied the pope's right to grant pardons on God's behalf in the first place: the only thing indulgences guaranteed, Luther said, was an increase in profit and greed, because the pardon of the Church was in God's power alone.

While Luther did not deny the pope’s right to grant pardons for penance imposed by the Church, he made it clear that preachers who claimed indulgences absolved buyers from all punishments and granted them salvation were in error.From this controversy the Protestant Reformation was launched.

Answer 2

Several Key players thought that the church profited to much from the people. Martin Luther to be one. Also note that during this period of religion it became ok to make a profit of of anothers labor. The barter system was no longer the primary economic system.