Feast of the Immaculate Conception
of Our Blessed Mother
O God, who didst wondrously preserve the Mother of Thine only-begotten Son from original sin in her Conception: grant, we beseech Thee: that strengthened by her intercession we may be ready with clean hearts to take part in her festival. Through the same Lord Jesus Christ Thy Son, who liveth and reigneth with Thee in the unity of the Holy Ghost, God, world without end. Amen.
(Collect of the Vigil Mass)
O Most Holy Virgin who wast pleasing to God and didst become His Mother. Immaculate in your body, in your soul, in your faith and in your love, we beseech thee to look graciously upon the wretched who implore thy powerful protection. The wicked serpent, against whom the primal curse was hurled, continues nonetheless to wage war and to lay snares for the unhappy children of Eve. Ah, do thou, our blessed Mother, our Queen and Advocate, who from the first instant of thy conception didst crush the head of our enemy, receive the prayers that we unite single-heartedly to thine and conjure thee to offer at the throne of God, that we may never fall into the snares that are laid for us, in such wise that we may all come to the haven of salvation; and in the midst of so many dangers may holy Church and the fellowship of Christians everywhere sing once more the hymn of deliverance, victory and peace. Amen.
Source: Saint Louis Catholic (https://stlouiscatholic.wordpress.com/)