This is the Liturgy of the Hours for December 31. Your local date is .
“’Finally the Immaculate Virgin, preserved free from all stain of original sin, when the course of her earthly life was finished, was taken up body and soul into heavenly glory, and exalted by the Lord as Queen over all things, so that she might be more fully conformed to her Son, the Lord of lords and conqueror of sin and death.’ The Assumption of the Blessed Virgin is a singular participation in her Son’s Resurrection and an anticipation of the resurrection of other Christians…’”
Today the Church honors the Assumption of the Blessed Virgin Mary, one of our Blessed Mother’s principal feasts and a holy day of obligation. Jesus took up and received His Mother in the totality of her being, a joyous union of God-bearer and Son. The earliest accounts of this mystery are from the 5th or 6th century. In the thirteenth century, Albert the Great, St. Aquinas, and St. Bonaventure endorsed the teaching, which was then a pious belief. In 1950 Pope Pius XII issued the apostolic constitution Munificentissimus Deus declaring “. . . for the glory of Almighty God, who poured his special affection upon the Virgin Mary for the honor of his Son . . . we pronounce, declare, and define it to be a revealed dogma that the immaculate Mother of God ever Virgin Mary, having completed the course of earthly life, was assumed body and soul into heavenly glory.” Our Mother’s Assumption is honored as the fourth Glorious Mystery in the Holy Rosary. 
Written by Sarah Ciotti
Reviewed by Fr. Hugh Feiss, OSB, STD
 Catechism of the Catholic Church, 2nd ed., 966, citing Pius XII, Deus Munificentissimus.
 Catholicpedia: The Original Catholic Encyclopedia (1917) for iPhone, iPad, and iPod Touch. s.v. “The Feast of the Assumption.”
 St. John, “The Dormition of the Holy Theotokos,” quoted by Prof. Stephen J. Shoemaker, http://pages.uoregon.edu/sshoemak/texts/dormindex.htm
 Pius XII, Deus Munificentissimus [Mary’s Glorification with Taking the Sky in Body and Soul], 1950.