"Every tree that does not bear good fruit shall be cut down and thrown into the fire."
St. Matthew 7:19
Saint David, son of the Prince of Cardigan and Non in Wales, was born in that land in the later fifth century, and from his earliest years gave himself wholly to the service of God. He began his religious life on the island of Wight, under Saint Paulinus, a disciple of Saint Germanus, Bishop of Auxerre, sent to Britain by Pope Saint Celestine to arrest the ravages of the heresy of a certain abbot named Pelagius, in the same region. When his virtue had grown strong by practice, he went to preach on the mainland; he built a chapel at Glastonbury and founded twelve monasteries, the principal one in the valley of Ross.
When heresy began to reappear in the early years of the sixth century, the bishops of the region assembled at Cardiganshire and sent for Saint David, already known to the people through his virtues and miracles, to come from his cell and preach to them. The Saint obeyed, and it is related that as he preached, the ground beneath his feet rose and became a hill, so that he was heard by a vast crowd. The heresy retreated and fell under the sword of the Spirit.
Saint David was elected Bishop of Caerleon. He could not resist the common will, but obtained that his see be transferred to a more retired location, today called Saint David, a lone and desert spot, where he would be able, with his monks, to serve God away from the tumults of the world.
When he was about eighty years of age, he recognized that his hour had come. As his agony closed, Our Lord stood before him in a vision, and the Saint cried out, Take me up with Thee! and so breathed forth his soul. The date was March 1, 561. Many Saints of Ireland and Great Britain, who revered him as their spiritual father, were formed in his monasteries, whose strict rule of prayer and work nourished their virtue and recommended them to both God and men.
Reflection. With whatever virtues a man may be endowed, he will discover, if he considers himself attentively, a sufficient depth of misery to afford cause for deep humility. But Jesus Christ says, He who humbles himself shall be exalted. (Luke 14:11)
Les Petits Bollandistes: Vies des Saints, by Msgr. Paul Guérin (Bloud et Barral: Paris, 1882), Vol. 3; Little Pictorial Lives of the Saints, a compilation based on Butler's Lives of the Saints and other sources by John Gilmary Shea (Benziger Brothers: New York, 1894)