Cardinal Séan Brady opened the Novena in Honour of Our Lady of Knock with a sermon at the Knock shrine in Mayo this afternoon.
The sermon touched on many issues, but emphasis was given to praying for victims of abuse.
"I want to pray for one group of people in particular; the people who have been broken and wounded through abuse of any kind", the Cardinal said.
"I pray that this Novena will be a source of healing and renewal of hope for each one of us and for our country and that it may be a powerful occasion of grace, mediated through Our Lady of Knock, the Mother of all Hope."
The Novena will take place over the next nine days. Some 150,000 people are expected to attend.