The Most Ancient Lives of Saint Patrick/The Life and Acts of St. Patrick/Chapter 67
Of the Voice that issued from the Sepulchre.
The holy standard-bearer of the Lord was accustomed to stop at the head-stone of every Christian who was buried outside of a burial-place, there to erect a cross; for he knew that in that country, then only lately converted unto the faith, all the dead, by reason of the fewness of the churches, could not be buried in consecrated ground; and therefore the good pastor wished by that blessed token to distinguish the sheep from the goats—namely, the Christians that were buried from the pagans. So might the worshippers of Christ, beholding the sign of life, understand that a servant of the faith of the cross was there buried, and so might they not delay to offer unto the Creator their prayers for his soul. Truly, a pious custom, and worthy is it of general observance that all who were baptized in the death of Christ, and are dead in his faith, should, when buried, have on them or near them the ensign of the death of Him.
And it came to pass that Patrick, in going out of Connactia, beheld outside of a burying-place which was consecrated to God the graves of two men who had been lately buried, and he observed that at the head of the one was a cross erected. And sitting in his chariot, as was then the custom, he bade his charioteer to stay, and, speaking to the dead man as to one living, he asked him who and of what religion he had been? And the voice answered unto him from the grave that he had been a pagan, altogether ignorant of the Christian faith. "Why, then," said the saint, "bearest thou the cross of Christ, thou who didst never worship or acknowledge Him?" And the voice answered: "He who is buried near me was a Christian; and some one of your faith, coming hither, placed the cross at my head." Thus the voice spake, and was silent. Then the saint descended from his chariot, and removed the cross from that place, and fixed it at the head-stone of him who had been baptized, and prayed for him, and went his way.