The responsorial psalm sung at the Midnight Mass of Christmas (in many Catholic lectionaries, the “Mass During the Night”) is a carefully crafted blend of Psalm 96 (95 in the Vulgate/Graeco-Latin numbering) with an antiphon drawn from the Gospel of the Nativity itself: “Today a Saviour has been born to us; he is Christ the Lord” (cf. Luke 2:11).

Psalm 96 is one of the “enthronement psalms” (Psalms 93–99), a collection that proclaims YHWH as king over all creation and all nations. Likely composed or finalized during the post-exilic period (after 538 BC), it reflects Israel’s renewed hope after the return from Babylon. The psalm calls the whole cosmos — heavens, earth, sea, fields, and trees — to rejoice because the Lord “comes to judge the earth” (v. 13). In its original context, this “coming” celebrated God’s sovereign rule, often linked to liturgical processions in the rebuilt Temple, where YHWH was enthroned above the ark.

For Christians, the Church brilliantly re-reads this royal enthronement psalm through the lens of the Incarnation. The repeated antiphon — “Today a Saviour has been born to us; he is Christ the Lord” — transforms the psalm’s announcement of God’s coming into a proclamation that the Judge and King has already arrived as a newborn child in Bethlehem. What Israel awaited as future (“he comes, he comes to judge the earth”) has, the Church celebrates as fulfilled on Christmas night.

Thus the entire created order, which the psalm originally summoned to praise YHWH’s kingship, now rejoices because the eternal Word has taken flesh. The “new song” (v. 1) becomes the song of Christmas; the “salvation day by day” (v. 2) is the eternal Today of the Incarnation; and the justice and faithfulness with which the Lord judges the world (v. 13) are revealed in the merciful face of the Child who is “Christ the Lord.”

At Midnight Mass, as the church stands in darkness awaiting the proclamation of the Nativity, this psalm with its luminous refrain perfectly expresses the astonishing mystery: the Judge has come not to condemn but to save, lying in a manger, and all creation sings for joy.