A soldier using a deck of ordinary playing cards as an aid to prayer and meditation dates back at least to 1788. The popular song Deck of Cards (sometimes known as "A Soldier's Prayer Book") was written in 1948 by "T." Texas Tyler. The song itself was based on a tract that was found sandwiched between the sheets of an old 1811 bible.
Ace: The one true God
Deuce: The Old Testament and New Testament in the Bible
Trey/Three: The Holy Trinity; the Father, the Son, and the Holy Spirit/Ghost
Four: St. Matthew, St. Mark, St. Luke, and St. John, evangelists and authors of the four Gospels
Five: The two groups of five virgins who trimmed their lamps for a wedding. Five were wise (by saving enough oil) and were admitted, while the other five were foolish (did not have enough oil) and were shut out.
Six: God created the Earth in six days.
Seven: God rested on the seventh day, now known as the Sabbath.
Eight: The eight righteous people whom God saved during the Great Flood: Noah, his wife, their three sons, and their wives.
Nine: Of the ten lepers whom Jesus cleansed, nine of them didn't even thank him.
Ten: The Ten Commandments God handed down to Moses.
King: Jesus Christ, King of Kings and Lord of Lords, or alternatively, God the Father.
Queen: Blessed Virgin Mary, the Mother of Jesus and Queen of Heaven.
Jack or Knaves: Satan or the Devil
365 Spots: Days in a year (basic deck actually contains 364 + one Joker, though most decks of cards will contain two jokers)
52 Cards: Number of weeks in a year
Thirteen Tricks: Number of weeks in a quarter
Four Suits: Approximate number of weeks in a month (can also mean the four seasons but this is not included in the song)
Twelve Face Cards: Number of months in a year