The Splendor of Truth (Veritatis Splendor)

Geertgen tot Sint Jans,
The nativity at night, c. 1490.
The National Gallery, London.

O God, who through the grace of adoption chose us to be children of light, grant, we pray, that we may not be wrapped in the darkness of error but always be seen to stand in the bright light of truth.  Through, etc.

Deus, qui, per adoptionem gratiæ, lucis nos esse filios voluisti, præsta, quæsumus, ut errorum non involvamur tenebris, sed in splendore veritatis semper maneamus conspicui.  Per, etc.

     Collect for the Thirteenth Sunday in Ordinary Time, new translation.  The CTS new daily missal, people's edition (London:  Catholic Truth Society, 2012), p. 825; Missale Romanum, 3rd (2002) ed., p. 463.  According to Corpus orationum at no. 6821, this is no. 725 in the late-9th-century Sacramentarium Bergomense (no. 725), which originated in northern Italy and possibly Milan.  Thus, it is not surprising that, before checking Corpus orationum, I found it in an 11th-century codex containing the Ambrosian (i.e. Milanese) rite (Manuale Ambrosianum pt. 2, Officia totius anni et alii ordines =Monumenta veteris liturgiae Ambrosianae 3, ed. Magistretti (Milan:  Ulricum Hoepli, 1905), 252; cf. the critical edition, also ed. Magistretti:  Monumenta sacra et profana, ex codicibus praesertim Bibliothecae Ambrosianae 4 (1913).  My translation:

O God, who through the adoption of grace, have willed that we be sons of the light, grant, we pray, that we may not be rolled/wrapped up into (enveloped/involved/entangled in) the darkness/obscurity of error but remain/continue (pass the night!) always conspicuous[ly] in (or adhere always conspicuous[ly] to) the splendor of truth.  Through, etc.

     Were it correct to read this as "grant, we pray, that we may not be enveloped in the darkness of error but pass the night always conspicuously in the splendor of truth", I would think of Ex 14:19-20, on the undoubtedly erroneous assumption that, unlike the Egyptian, the Israelite camp would have been illuminated by the pillar of fire (13:21-22)).  I would thus envision the Israelites enveloped by the darkness of the Egyptian night, but separated from the advancing enemy by the cloud while yet lit up by the pillar.  I would think also (so long as I hadn't checked the Latin?) of Luke 24:29 and the evening prayer, "Lord Jesus, stay with us, for evening is at hand, and the day is past" (1979 BCP 124, 139; ).  As for the reading "pass the night", see Lewis & Short, s.v. maneo I.B.
     And Who is the Splendor of Truth?

O God, whose eternal Word adorns the face of the heavens yet accepted from the Virgin Mary the frailty of our flesh, grant, we pray, that he who appeared among us as the splendour of truth may go forth in the fullness of power for the redemption of the world. Who, etc.

Deus, cuius Verbi æternitas cæli faciem decoravit, et ex Maria Virgine carnis nostræ fragilitatem suscepit, quæsumus, ut qui splendor veritatis in nobis apparuit, pro mundi redemptione in plenitudine potestatis procedat.  Qui, etc.

     Collect for the Monday after the Solemnity of the Epiphany, new translation.  The CTS new daily missal, people's edition (London:  Catholic Truth Society, 2012), p. 1291; Missale Romanum, 3rd (2002) ed., p. 178.