When a man or woman enters a religious order, they typically receive a new name that they are called by their religious community.
Traditions vary by each community, as some receive the name from their religious superior, while others are able to prayerfully choose their own name.
In the case of St. John of God, a holy religious saint of the 16th century, he received his name from God himself in a vision.
According to the Catholic Encyclopedia, early in his adult life John, "On the advice of his confessor he soon returned to Gibraltar, where, brief as had been the time since the invention of the printing-press, he inaugurated the Apostolate of the printed page, by making the circuit of the towns and villages about Gibraltar, selling religious books and pictures, with practically no margin of profit, in order to place them within the reach of all."
It was at this time in his life that he had a vision.
Hugh Francis Blunt narrates what happened next in his 1921 book, Great Penitents:
One day while he was engaged in this work of apostleship, the Infant Jesus appeared to him and affectionately called him, "John of God," and directed him to repair to the city of Granada. Without knowing why, John closed his little shop and set out for that city.
Once there, he was inspired by the preaching of St. John of Avila, and began a life of charity towards the poor.
Eventually the local bishop gave him a habit to wear and imposed upon him the religious name, "John of God," that the Infant Jesus named him.
His followers would later establish a new religious order called, "Brothers Hospitallers of St. John of God."
