The birth of Mary became a source of great joy for Joachim, Mary’s father. According to the words of the Angel to Joachim: "Joachim, rejoice! God has heard your prayer and your wife Anna shall conceive and give birth to a daughter, whose nativity will become joy for the entire world." Consequently, the feast is celebrated in the spirit of general rejoicing and exaltation.
The celebration of Mary's nativity was established on September 8, since on that day the basilica in honor of the Nativity of the Blessed Virgin Mary was dedicated in Jerusalem.
The day of the Nativity of the Mother of God is a day of universal joy, because through the Mother of God, the entire human race was renewed.