▼ Heb “and he has given us light.” This may be an elliptical expression, with “his face” being implied as the object (see Num 6:25; Pss 31:16; 67:1; 80:3, 7, 19). In this case, “his face has given us light” = “he has smiled on us,” or “he has shown us his favor.” Another option (the one reflected in the translation) is that “light” here symbolizes divine blessing in the form of deliverance. “Light” is often used as a metaphor for deliverance and the life/blessings it brings. See Pss 37:6; 97:11; 112:4; Isa 49:6; 51:4; Mic 7:8. Some prefer to repoint the form וְיָאֵר (v^eya’er; vav [ו] conjunctive + jussive) and translate the statement as a prayer, “may he give us light.”

▼ The Hebrew noun חַג (khag) normally means “festival,” but here it apparently refers metonymically to an offering made at the festival. BDB 291 s.v. חַג 2 interprets the word in this way here, citing as comparable the use of later Hebrew חֲגִיגָה, which can refer to both a festival and a festival offering (see Jastrow 424 s.v. חֲגִיגָה).

▼ The second half of v. 27 has been translated and interpreted in a variety of ways. For a survey of major views, see L. C. Allen, Psalms 101–150 (WBC), 122.