Pro-life group Human Life International has asked for the offering of 1,000 Masses for the referendum, and has a form on their website where the Masses offered for this intention may be added to the calendar.
In his video, Fr. O'Reilly recalled Pope John Paul II's 1979 visit to the country, during which he urged Irish citizens to defend life.
"He said to the Irish people 'you must protect life;' he knew what was coming down the road. And so the Irish people took this very, very seriously and rosary crusades began all around the country," O'Reilly said.
This also led to the proposal of the constitutional amendment that is currently in place, which gave equal protection to mother and child "so that Ireland would be a country that in the constitution would say that the unborn child has a right to life."
"This was an incredible gift from God for our country because it meant that the politicians couldn't just bring in abortion when they wanted. They would have to put it to the people," he added. "And so we fought it for years and years and now in 2018 we're being asked to vote on abortion."
The Ancient Order of Hibernians, a Catholic Irish-American men's fraternity, has asked its members to set aside May 18 as a day of prayer in solidarity with the Save the 8th Campaign.
"Every prayer for a 'No' vote is a compassionate plea to spare Ireland the pain America has suffered for 45 years," Ancient Order of Hibernians National President James F. McKay said, alluding to the 1973 U.S. Supreme Court decisions that mandated legal abortion across the country.
He encouraged prayers invoking the Most Sacred Heart of Jesus and Our Lady of Fatima to "save Ireland's mothers and unborn from the evils of abortion."
He also encouraged immediate social media outreach as well as discussions with family and friends about "the importance of protecting the unborn."
Bishop James D. Conley of Lincoln, Neb. used his May 18 column in the Southern Nebraska Register to ask readers to join him in prayer that the people of Ireland will choose life.
"I pray that the people of Ireland will see that the legalization of abortion in countries around the world has not made women free. That abortion has only caused more violence, more ruin, and more despair," Bishop Conley said.
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The bishop said the Catholic faith "has long given the Irish people an acute and attentive sense of human dignity, human rights, and justice," but Ireland has secularized in part due to "Church leaders who failed to give authentic and faithful witness to the Gospel."
Conley, who spent a semester in Ireland as a 20-year-old recent Catholic convert, said "my introduction to the day-to-day practice of my newfound Catholic faith was in Ireland."
"It has now been over 40 years since I spent those four delightful months in Ireland, but I still remember vividly the strong faith of the Irish people and how Catholicism ran deep in the Irish soil and soul. I owe so much to the Irish people for nurturing me in my Catholic faith. And we, as a country, owe so much to the Catholic Church in Ireland for bringing that same faith to these shores."