Of the four collects provided on page 38 of the Book of Common Prayer, 2019, the first three are drawn from the Canadian Prayer Book of 1962, where they are appointed as Prayers at Mid-Day for Missions. They were written by various ministers in the late 19^th century. The fourth collect is the collect for The Annunciation, and is derived from the Angelus, a traditional Western devotion concerning the Blessed Virgin Mary.

Blessed Savior, at this hour you hung upon the Cross, stretching out your loving arms:
Grant that all the peoples of the earth may look to you and be saved;
for your tender mercies’ sake. Amen.

This brief prayer holds together the traditional midday devotional focus on the Cross with a modern-tradition devotional focus on the mission of the Church. Our Savior’s will to “draw all people unto myself” becomes the object of our prayer.

Almighty Savior, who at mid-day called your servant Saint Paul to be an apostle to the Gentiles:
We pray you to illume the world with the radiance of your glory,
that all nations may come and worship you;
for you live and reign with the Father and the Holy Spirit, one God, for ever and ever. Amen.

This prayer reflects upon the conversion of St. Paul, which took place at this time of day, and asks God to provide similar enlightenment to the whole world. Although the Cross is the primary traditional devotional object at midday, this and the following collect bring us to other important biblical events that took place at or near this hour.

Father of all mercies, you revealed your boundless compassion
to your apostle Saint Peter in a three-fold vision:
Forgive our unbelief, we pray,
and so strengthen our hearts and enkindle our zeal,
that we may fervently desire the salvation of all people,
and diligently labor in the extension of your kingdom;
through him who gave himself for the life of the world, your Son our Savior Jesus Christ. Amen.

Recounting the story in Acts 10, we pray for the same zeal and vigor that St. Peter received for the Gentiles about midday (“the sixth hour”). Like many good prayers, this collect leads us to ask for a change of heart before a change of action – we ought to “fervently desire” the mission of Christ to advance if we are to “diligently labor” to see it carried out.

Pour your grace into our hearts, O Lord,
that we who have known the incarnation of your Son Jesus Christ,
announced by an angel to the Virgin Mary,
may by his Cross and passion be brought to the glory of his resurrection;
who lives and reigns with you, in the unity of the Holy Spirit, one God, now and for ever. Amen.

Although not specifically labeled as such, this collect is especially appropriate for Saturdays. Much like how Sundays commemorate the resurrection and Fridays the crucifixion, Saturdays are traditionally a day of Marian devotion in historic Western piety. This prayer, in particular, plays well into that rhythm of spirituality because it appeals to Christ’s “Cross and passion” (Friday) to lead us to “the glory of his resurrection” (Sunday), assuming we pray this in between those days, on Saturday.