De Locis Sanctis, 670
In his transcription of De Locis Sanctis, the Irish bishop Adamnan provides us with an account of the pilgrimage to the Holy Land undertaken by the Frankish bishop Arculf in the middle of the seventh century.
The description lingers on the places of worship in Bethlehem, and along with the Church of the Nativity a number of so-called minor sanctuaries are mentioned, including Shepherds’ Fields, Rachel’s Tomb and the place known as the Washing of Jesus.
III - The rock situated beyond the wall, upon which the water from the first washing after his birth was poured
Here I think I must briefly mention the rock lying beyond the wall, upon which the water of the first bathing of the Lord's body after his birth was poured from the top of the wall out of the vessel into which it had been put.
This water of the sacred bath, poured from the wall, found a receptacle in a rock lying below, which had been hollowed out by nature like a trench: and this water has been constantly replenished from that day to our own time during the course of many ages, so that the cavity is shown full of the purest water without any loss or diminution, our Savior miraculously bringing this about from the day of his nativity, of which the prophet sings: “Who brought water out of the rock”, and the Apostle Paul, “Now that Rock was Christ” who, contrary to nature, brought a stream of water out of the hardest rock in the desert to console his thirsting people.
Such is the power of God and the wisdom of God, who also brought out water from that rock of Bethlehem and keeps its cavity always full of water; this our Arculf inspected with his own eyes, and he washed his face in it.