Shavuot is a time of remembering . . . and it is not limited to just Act 2.  There is a biblical continuity of Shavuot that starts in the Torah and runs through the New Testament.  The book of Hebrews warns us to never refuse the voice of God (Him who speaks).  The voice of God is also connected to correction and the coming shaking.  To be prepared for life and the unfolding of Bible prophecy, we must hear the voice of Him who speaks in our generation!