Saint Patrick did more than drive all the snakes out of Ireland. He was a Christian in a population that was mostly pagean. It is said that he recited this prayer every morning. It is known as Saint Patrick's Breastplate".
The hymn whose original old Irish lyrics were traditionally attributed to Saint Patrick and his Irish ministry in the 5th century is written in the style of a druidic incantation for protection on a journey.
The words were translated into English verse by Cecil Frances Alexander in 1889 and set to two traditional Irish tunes, "St. Patrick" and "Deirdre". The hymn, also known by its opening line "I bind unto myself today", is currently included in the many modern day church hymnals.
It is often sung during the celebration of the Feast of Saint Patrick on or near March 17, as well as on Trinity Sunday. In many churches it is unique among hymns because the variations in length and metre of verses mean that at least three different tunes must be used.
Check ou this You Tube being performed by present day Christian artist Steve Bell