Importance of the Old Testament, or the Hebrew Scriptures have for Christian formation

  What practical importance does the Old Testament, or the Hebrew Scriptures have for Christian formation? Using a set of Sunday readings at Catholic Mass as an example, explain the correlation between the first reading from the Old Testament and the gospel (outside of the Easter Season). Note: If you wish to find the Sunday readings online, go to http://www.usccb.org/ Mass Readings.