The Most Ancient Lives of Saint Patrick/The Life and Acts of St. Patrick/Chapter 70
A Fountain is produced out of the Earth.
And Saint Patrick, while abiding in this village, was entertained at the house of a woman who often in his presence complained of the want of fresh water. For the river that ran near it was, by the flowing in of the tide of the sea, made wholly salt of taste; nor before the return thereof could any fresh water be obtained, unless drawn at a great distance. But the saint, who continually thirsted after God, the living fountain, compassionated the grievance of his hostess and of the multitude then newly born unto Christ, and, the rather that they might the more ardently pant toward the fountain of life, thought he fit to show its virtue. Therefore on the morrow he went unto a certain place, and in the presence of many standing around he prayed, and touched the earth with the staff of Jesus, and in the name of the Lord produced from it a clear fountain. Thus with the staff in the hand of his preacher Saint Patrick did the Lord renew the miracle which of old time he had deigned to work by the rod in the hand of Moses striking the rock; there the rock twice struck flowed forth abundant waters; here the earth once pierced poured forth a pure fountain. And this is the fountain of Dublinia, wide in its stream, plenteous in its course, sweet to the taste, which, as is said, healeth many infirmities, and even to this day is rightly called the fountain of Saint Patrick.