"Those who do not learn history are doomed to repeat it." This phrase is applicable to heretical doctrines that pop up in different times.

What do the Orthodox and Protestants share in common? They both reject the authority of the pope.

The doctrine of hell is no doubt a major reason why some people are hesitant about Christianity. How could an all-loving God create hell?

Christians today take it for granted that the person of Jesus possesses two natures: one human and one divine.

Many Protestants reject the title "Mother of God" for Mary. However, this position leads to an ancient heresy that denies Jesus' divinity.