A novena is simply defined as a nine-day period of private or public prayer to obtain special graces, to implore special favors, or make special petitions. Novena is derived from the Latin novem, meaning nine. Many Novenas are set by the liturgical calendar and are tied to specific feast days. For example, The Divine Mercy Novena starts every year on Good Friday and the Novena to the Holy Spirit every year on Ascension Thursday leading to the Feast of Pentecost. Scholars will, in fact, point to the Novena to the Holy Spirit as the Biblical Roots of the Catholic devotion. In Acts 1:12, 14 it is written, “After that they returned to Jerusalem from the mount called Olivet near Jerusalem — a mere Sabbath’s journey away. Together they devoted themselves to constant prayer." It was nine days after the Ascension that the Holy Spirit descended upon the Apostles.
Often, Catholics will pray Novenas in times of need or to specifically ask for special favors. The Novena to St. Jude and Novena to St. Joseph each begin nine days before their Feast Days, but can bep rayed in a particular time of need as well. The same can be true of the Novena to St. Peregrine, the Patron Saint of Cancer Patients as those daignosed with cancer and their families are known to pray this novena upon diagnosis and treatment.