The story in this video sites the Christian Fable, yet the tradition pre-dates Christianity:
Brigid’s cross and its spiritual tradition in Ireland is far older than Christianity. The Goddess Brigid was one of the Tuatha Dé Danann. Her feast day was the feast of Imbolc, and the cross made of rushes today is very likely the descendant of a pagan symbol whose original meaning may have been locally understood even into the early 20th century in rural Ireland. One remnant of that tradition in the meaning of the Brigid’s Cross today, is that it is said to protect a house from fire.