We continue to take a look back at the 100 years of broadcasting God's Word on Moody Radio.  If you missed any of our broadcasts head to www.moodypresents.org.   We are so thankful for God's faithfulness in continuing this ministry through the years.  Today in our retrospective series we'll hear beloved former president of the Moody Bible Institute, Dr. Joe Stowell on how the most important thing we can do is to guard our hearts.  Let's hear what that means.