Priests and bishops share the public's anger and distress at the church's mishandling of clerical child sex abuse, it has been claimed.
Marking Reek Sunday on Croagh Patrick, Archbishop of Tuam Michael Neary said it was understandable that practising Catholics felt discouraged by recent revelations.
He said the Church had been shaken by wrongdoing.
"We are very conscious of the difficulties on life's journey, the enormous difficulties besetting our Church, chiefly in the number of innocent people who have suffered through the wrong-doing of some priests," he said.
"It is understandable that many good and faithful Catholics experience distress and discouragement after the revelations of the mishandling of abuse cases.
"Many are angered and appalled by what they have learnt. Indeed, these feelings are shared by priests, religious and, yes, bishops too."
Archbishop Neary celebrated mass on the summit of Croagh Patrick in Co Mayo for the annual Reek Sunday pilgrimage.
Mayo Mountain Rescue estimated that up to 20,000 people climbed the mountain in foggy conditions.
Some 120 rescue personnel were on duty, with a spokesman stating that up to 50 people had been treated for minor ailments by mid afternoon.