Someone kindly left a comment on my last post about our recent 40 Hours Devotion asking about the origins of the devotion. Here is a brief explanation of the reasons and history behind the 40 Hours Devotion.
For us Catholics, the Mass is our central act of worship. It is an act that participates in the eternal reality of Our Lord's passion, death and resurrection. Many Catholics also wish to be able to pray in the presence of the Blessed Sacrament outside of Mass.
The Second Vatican Council upheld and strongly encouraged adoration of the Blessed Sacrament outside of Mass. Such devotion arises from the Sacrifice of the Mass and serves to move us to both sacramental and spiritual communion with Our Lord. Blessed John Paul II repeatedly highly recommended public and private devotion of the Blessed Sacrament including procession of the Blessed Sacrament on the Feast of Corpus Christi and the 40 Hours Devotion.
The number 40 has historically, since very ancient times, signified a 'sacred' period of time.
The rain during the time of Moses lasted 40 days and nights; the Jews wandered in the desert for 40 years before arriving at the Promised Land; Jesus fasted and prayed for 40 days before beginning his public ministry; we observe Lent for 40 days and we also remember the tradition 40 hour period from Our Lord's burial until his resurrection.