this midday moment of rest
is your welcome gift.
Bless the work we have begun,
make good its defects,
and let us finish it in a way that pleases you.
Grant this through Christ our Lord.
Midday prayer for Wednesday, Liturgy of the hours (1975). Cf. the Universalis translation here (English) and here (Latin and English).
This has been taken up in various Protestant "breviaries" as well, e.g. the 1993 Book of common worship (PCUSA), no. 502, p. 548 (but before that Daily Prayer: the worship of God, Supplemental liturgical resource 5 (The Westminster Press, 1987)), and the 1992 United Methodist book of worship, which miscredits "The Westminster Press/John Knox Press, U.S.A., 20th cent.").
Omnípotens et miséricors Deus, qui nos die média respiráre concédis, quos cœpimus propítius intuére labóres, et, sanans quæ delíquimus, fac eos ad finem tibi plácitum perveníre. Per Christum.
Almighty and merciful God, who allow us at midday to catch [our] breath, attend graciously to the works [(masc)] we have begun, and, making good [the failings for] which [(neut)] we have been responsible [(deliquimus, we have failed, been lacking; have committed)], cause them [(masc)] to attain to an end pleasing to you. Through Christ.
Oratio Ad Sextam, Day IV, Liturgia horarum (1971). This one does not appear in Corpus orationem. I therefore conclude that it was composed anew for Liturgia horarum.
My thanks to Joe Chambers for bringing this one to my attention.