The six Holy Days of Obligation in the Catholic church are Solemnity of Mary - Mother of God, Feast of the Ascension of Our Lord, Assumption of the Blessed Virgin Mary, All Saints' Day, Feast of the Immaculate Conception and Christmas. Holy Days of Obligation are days on which followers of the Catholic faith must attend mass and avoid servile work, if able.
Solemnity of Mary, Mother of God, is observed on January 1. This day is set to remind Catholics of how the Blessed Virgin plays a role in salvation. The Christmas birth of Jesus Christ happened, on Mary's part, due to her acceptance of conception by proclaiming to God, "Be it done unto me according to Thy word," while the Feast of the Ascension of Our Lord, the final act of redemption that Jesus Christ began on Good Friday, celebrates his bodily ascension into heaven as witnessed by his apostles. This day of obligation is observed 40 days after Easter Sunday.
The Assumption of the Blessed Virgin Mary is observed annually on August 15. The Assumption serves to commemorate the passing of Mary, as well as her earthly body's assumption into heaven before the body began to decay. Many believe this act lead to the swift time line in which Christians eulogize and bury their dead, along with the belief of all soul's bodily resurrection.