"With Heart & Voice" is a weekly radio program that features sacred music related around a certain theme.  This week's theme is Saints Peter & Paul, since their memorial feast day is coming up on June 29.  Once of the most famous text from this Mass is, "Tu est Petrus," or in English, "You are Peter, and on this rock I will build my Church," from Matthew 16:18.  There are many musical settings of this text, two of which are included in this program.  Enjoy!