Based on the ancient ordering of days to a specific spiritual theme
As the Catechism of the Catholic Church explains, “In the liturgical year the various aspects of the one Paschal mystery unfold” (CCC 1171). While this chiefly refers to the annual cycle of seasons, from Advent to Easter, the Church also traditionally sees every week as an unfolding of the mystery of Christ.Over time there developed a tradition that assigned each day of the week a different spiritual theme. This was most clearly revealed in the regulations regarding the celebration of Votive Masses.
When a priest says Mass throughout the week, he has various options about what prayers he can use. Most often they reflect the feast of a particular saint, but on certain days the priest is allowed to celebrate a Votive Mass that highlights a particular aspect of the faith. For centuries this was restricted to certain Masses in connection to the spiritual theme of the day.
These themes were repeated each week and allowed the priest (and faithful) to have a primary focus to their work days. Most of these themes are connected to various historical events that happened on a specific day of the week (i.e. Holy Eucharist on Thursdays, because the Last Supper occurred on a Thursday).
Below is a different prayer for each day of the week based on the prayers of the Votive Masses found in the current Roman Missal.
Mondays – Most Holy Trinity
God our Father, who, by sending into the world the Word of truth and the Spirit of sanctification, made known to the human race your wondrous mystery, grant us, we pray, that in professing the true faith we may acknowledge the Trinity of eternal glory and adore your Unity, powerful in majesty.
Tuesdays – The Holy Angels
O God, who dispose in marvelous order ministries both angelic and human, graciously grant that our life on earth may be defended by those who watch over us as they minister perpetually to you in heaven.
O Lord, under the faithful protection of your Angels, may we advance boldly along the way of salvation.
Wednesdays – St. Joseph
O God, who in your inexpressible providence were pleased to choose Saint Joseph as spouse of the most holy Mother of your Son, grant, we pray, that we, who revere him as our protector on earth, may be worthy of his heavenly intercession.
Lord, may we live for you always in justice and holiness, helped by the example and intercession of Saint Joseph, who in carrying out your great mysteries served you as a man just and obedient.
Thursdays – The Holy Eucharist
O God, who have accomplished the work of human redemption through the Paschal Mystery of your Only Begotten Son, graciously grant that we, who confidently proclaim, under sacramental signs, the Death and Resurrection of Christ, may experience continued increase of your saving grace.
May sharing at the heavenly table sanctify us, Lord, we pray, so that through the Body and Blood of Christ the whole family of believers may be bound together.
Fridays – Most Sacred Heart of Jesus
Clothe us, Lord God, with the virtues of the Heart of your Son and set us aflame with his love, that, conformed to his image, we may merit a share in eternal redemption.
O God, Father of mercies, who, because of the great love with which you loved us, with untold goodness gave us your Only Begotten Son, grant, we pray, that, being perfectly united with him, we may offer you worthy homage.
Saturdays – Blessed Virgin Mary
O God, who chose the Blessed Virgin Mary, foremost among the poor and humble, to be the Mother of the Savior, grant, we pray, that, following her example, we may offer you the homage of sincere faith and place in you all our hope of salvation.
May the venerable intercession of Blessed Mary ever-Virgin come to our aid, we pray, O Lord, and free us from every danger, so that we may rejoice in your peace.