"He maketh me to lie down in green pastures: He leadeth me beside the still waters" (Psalm 23:2).
This date has traditionally been associated with the annual "feast of St. Patrick," observed especially in Ireland, where the missionary Patrick was largely instrumental in converting that nation from paganism (the Druid religion in particular) to Christianity back in the fifth century A.D. Although his remaining writings indicate that his preaching and the churches he founded were largely evangelical, and although he was never officially canonized as a "saint" by the Roman church, his "day" has been commonly known as "St. Patrick's Day" for over a thousand years.
It is also interesting that this particular day has often been observed by both Protestants and Catholics wearing green clothing. Ireland has been called the "Emerald Isle" because of its beautiful green verdure.
God has graciously clothed the lands of all His creation (not just Ireland) with beautiful, eye-soothing, green grass and trees. (Think how eye-jarring it would be if all the world were clothed in purple or orange!)
The beloved Twenty-third Psalm especially incorporates the earth's green clothing as a metaphor for the spiritual rest believers find in Christ, like sheep following their shepherd. "He maketh me to lie down in green pastures," alongside the turbulent waters that had become beautiful "stilled waters" at the voice of "that great shepherd of the sheep" (Hebrews 13:20) when He said: "Peace, be still" (Mark 4:39).
"I will feed them in a good pasture. . . . and I will cause them to lie down, saith the Lord God. I will seek that which was lost, and bring again that which was driven away, and will bind up that which was broken. . ." (Ezekiel 34:14-16). HMM