Office of Readings: the considerably shortened Hymn: according to current use a movable hour.

Attributed to Pope St. Gregory the Great (540-604). In the Roman Breviary this hymn is used in its entirety for Matins from the first Sunday in Lent until the Saturday before Passion Sunday. Today the hymn is still used, but from Ash Wednesday until the Fifth Sunday of Lent and it is broken into two hymns. The first half, Ex more docti mystico, is used for the Sunday Office of the Readings. The second half, Precemur omnes cernui is used for Sunday Lauds. 

1. The Fast as taught by holy lore

We keep in solemn course once more;

The fast to all men known, and bound

In forty days of yearly round.

2. The law and seers that were of old
In divers ways this Lent foretold
Which Christ, all seasons’ king and guide,
In after ages sanctified.

3. More sparing therefore let us make
The words we speak, the food we take,
Our sleep and mirth, and closer barred
Be every sense in holy guard.

7. Forgive the sin that we have wrought;
Increase the good that we have sought;
That we at length, our wanderings o’er,
May please Thee here and evermore.

8. We pray Thee, holy Trinity,
One God, unchanging Unity,
That we from this our abstinence
May reap the fruits of penitence.