Psalm 29 (Psalm 28 in the Vulgate numbering) is a majestic hymn of praise attributed to David, celebrating the Lord's sovereign power manifested in a thunderstorm. Scholars consider it one of the oldest psalms, possibly dating to the 10th–12th century BCE, with roots in ancient Near Eastern traditions. Many experts note striking parallels with Canaanite mythology, particularly hymns to the storm god Baal, who was depicted as thundering over waters and subduing chaos. The Israelite poet likely adapted this imagery, substituting Yahweh for Baal to assert the Lord's supremacy over rival deities and natural forces. The psalm's vivid description—"the voice of the Lord" thundering seven times (symbolizing completeness)—evokes lightning, wind, and flooding rains, portraying God as enthroned above the primordial "flood" (echoing Genesis creation and Noah's deluge), taming chaos and establishing order.

In its liturgical form for the Feast of the Baptism of the Lord, the responsorial psalm uses selected verses (29:1-2, 3ac-4, 3b, 9b-10) with the refrain: "The Lord will bless his people with peace." This feast, marking the end of the Christmas season, commemorates Jesus' baptism in the Jordan, where the heavens opened, the Spirit descended, and the Father's voice declared, "This is my beloved Son." The psalm's emphasis on the divine voice "upon the waters" and "the immensity of waters" directly evokes the baptismal scene, symbolizing God's creative and redemptive power over water—from primordial chaos to the waters of rebirth in Christ.

Its significance in the Mass lies in proclaiming Christ's manifestation (Epiphany) as the beloved Son, anointed by the Spirit. The thunderous "God of glory" contrasts with the gentle peace bestowed on God's people, foreshadowing the blessing of baptismal grace: strength amid turmoil and ultimate peace through union with Christ. This ancient hymn thus bridges Old Testament theophany with New Testament revelation, inviting worshippers to ascribe glory to the Lord who reigns forever.