Marcus Grodi and Msgr. Jeffrey Steenson continue to unpack Book V of "Against Heresies" by St. Irenaeus of Lyons. St. Irenaeus points out some of the key errors of the popular heresies of his day. Underlying all of them is an ignorance, sometimes unintentional and sometimes willful, of the importance of the deposit of faith passed down by the apostles. The proponents of these wrong ideas are certainly people of intelligence; but because they've become infatuated with their intelligence, they've fallen into the trap of preferring new ideas to the carefully preserved teaching of the Church. For more episodes, visit deepinhistory.com.