Drawing the Sortes Sanctorum (Lots of the saints) or Sortes Sacrae (Holy Lots) was a type of divination or cleromancy practiced in early Christianity, derived and adapted from the ancient Roman sortes, as seen in the Greek Sortes Homericae and Roman Sortes Virgilianae.
Some early Christians went to church and listened for the words of scripture that were being sung when they entered the church as a random means of predicting the future and God's will (along the lines of the Jewish Bath Kol form of divination), but the Sortes was done more formally, by casually opening the Holy Scripture and reading the first words to come to hand, with these words being taken to foretell the inquirer's fate. Doing so was often a public event, and sometimes accompanied by ceremonies (such as the 7th century emperor Heraclius ordering 3 days' public fast before a consultation as to whether or not he should advance or retreat against the Persians - he took the text that arose as divine instruction to winter in Albania). Since full copies of the Christian Bible were rare before printing was invented, the lots usually used the Psalms, the Prophets, or the four Gospels.
Sortes Sanctorum Wikipedia
Gregory of Tours relates that Merovech used the Sortes to check the predictions of a female fortune-teller that he would (as he hoped) gain the kingdom of his father Chilperic. He had the Psalter, the Books of Kings, and the four Gospels placed on the shrine of St. Martin and held a time of fasting and prayer, but the texts he then drew stated that he would not and were later interpreted as predicting his later ruin.
A French writer, in 506, says, "this abuse was introduced by the superstition of the people, and afterwards gained ground by the ignorance of the bishops.", as is shown by Pithon's Collection of Canons, which contains some forms under the title of The Lot of the Apostles. These were found at the end of the Canons of the Apostles in the Abbey of Marmousier, and various canons were made at later councils and synods (such as the councils of London under Archbishop Lanfranc in 1075, and Corboyl in 1126) against the Sortes as superstition. However, they were still occurring in the time of St Francis of Assisi who, in denying himself any possessions except coats and a cord, wanted to check if he was still allowed to own books. He prayed and then drew Mark, chapter IV, "Unto you it is given to know the mystery of the kingdom of God; but unto them that are without, all these things are done in parables", which he took to mean that he was neither allowed books nor needed them. While seeking divine guidance, St. Francis is also said to have thrice opened to a random page of the book of Gospels in the church of St. Nicholas. In each time he opened to a passage in which Christ told His disciples to leave their earthly belongings and follow Him.
A Peter of Toulouse, who had sworn on the Bible that accusations of heresy against him were false, was immediately afterwards convicted by the Sortes when a bystander grabbed the Bible and opened it randomly at the words of the demon Legion to Jesus, "What have we to do with thee, thou Jesus of Nazareth?", which he adjudged to mean that Peter had nothing to do with Jesus.
At the acclamation of Martin as bishop of Tours (371) a few cast aspersions, largely for his lack of personal glamor. According to the Vita by Sulpicius Severus:
St. Augustine related, in his autobiographical Confessions, how his conversion to the Catholic faith was assisted by a voice chanting tolle lege or 'take up and read':In Running with Scissors (2002) by Augusten Burroughs, the eccentric psychiatrist Dr. Finch performs bibliomancy using the Bible.
In The Holy Thief (1992) by Ellis Peters, the monks of Shrewsbury Abbey determine ownership of the relics of Saint Winifred through the sortes Biblicae.
In The Ash-Tree (1904) by M. R. James, a country vicar uses a Bible for "that old and by many accounted Superstitious Practice of drawing the Sortes" after the mysterious death of his friend.
In Far from the Madding Crowd (1874) by Thomas Hardy, Bathsheba is persuaded to perform bibliomancy. She sends an ill-fated valentine to Boldwood on the strength of this reading.
In The Sirens of Titan (1959) by Kurt Vonnegut, Jr., Malachi Constant inherits (and squanders) the largest family fortune in 22nd century America. Constant's late father was regarded as an investor of preternatural ability. The elder Constant planned enormous stock-market transactions (always wildly successful) following simple procedures derived from idiosyncratic rules. Ultimately he refused ever to leave the motel room where his empire began: with only himself and a Gideon Bible.