free your Church from sin
and protect it from evil.
Guide us, for we cannot be saved without you. . . .
Oratio, Evening prayer, Liturgy of the hours (Christian prayer, p. 323); and Collecta, Roman missal (cf. CTS new daily missal, p. 1384, below), Monday, Third Week of Lent.
Something about that fourth line of the old English translation (now a hangover in the Liturgy of the hours) always takes my breath away, though it is an inaccurate rendition of the mid-8th-century, Gelasian-Sacramentary original:
Ecclesiam tuam, Domine, miseratio continuata mundet et muniat, et, quia sine te non potest salva consístere, tuo semper munere gubernetur. . . .
Here is but one translation:
May thy continued mercy, O Lord, cleanse and defend thy Church; and because, without thee, she cannot keep safe, may she be always governed by thy gift....
And here it is the 2010 English Missal (CTS new daily missal, p. 1384):
May your unfailing compassion, O Lord,cleanse and protect your Church,and, since without you she cannot stand secure,may she be always governed by your grace. . . .
It is there in the 1979 Book of common prayer, too, where it appears on pp. 180 and 232 as Proper 13:
. . . let thy continual pity cleanse and defend thy Church, and, because it cannot continue in safety without they succor, preserve it evermore by thy help and goodness. . . .
Let your continual mercy, O Lord, cleanse and defend your Church; and, because it cannot continue in safety without your help, protect and govern it always by your goodness. . . .
In the earlier Books of common prayer and the Sarum missal (which adds the quæsumus) it is assigned to the 16th Sunday after Trinity:
[1549:] Lord, we beseche thee, let thy continual pitie clense and defende thy congregacion; and, because it cannot continue in safetie without thy succoure, preserue it euermore by thy helpe and goodnes. . . .
[1662:] O Lord, we beseech thee, let thy continual pity cleanse and defend thy church; and because it cannot continue in safety without thy succour, preserve it evermore by thy help and goodness. . . .