Psalm 118 (known as Psalm 117 in the Septuagint and Vulgate numbering) is a jubilant hymn of thanksgiving that concludes the Egyptian Hallel (Psalms 113–118). These six psalms were traditionally sung at major Jewish festivals, especially Passover, recalling God’s deliverance of Israel from Egypt. Its origins are debated among scholars, but it likely dates to the post-exilic period, around the dedication of the Second Temple in 515 BC, though it draws on earlier Davidic traditions of royal thanksgiving. The refrain “his mercy endures for ever” echoes the covenant language of Exodus and appears in accounts of the Temple’s foundation (Ezra 3:11), suggesting its use in processional liturgy and communal worship celebrating national restoration after exile.

The selected verses (2–4, 13–15b, 22–24) form an antiphonal litany. They summon the house of Israel, the priests (house of Aaron), and all who fear the Lord to proclaim God’s steadfast mercy (ḥesed). The psalmist then testifies to personal deliverance: “They pushed me, pushed me hard to knock me down, but the Lord was my helper.” This leads to the triumphant declaration that the Lord is strength, song, and saviour, evoking shouts of joy “in the tents of the righteous.” The climax reinterprets a building metaphor: “The stone that the builders rejected has become the cornerstone,” a marvel wrought by the Lord. It ends with the famous invitation: “This is the day the Lord has made; let us rejoice in it and be glad.”

In the Roman Catholic Lectionary, these verses with the response “Give praise to the Lord, for he is good, his mercy endures for ever” (or Alleluia) serve as the Responsorial Psalm for the Mass of the Second Sunday of Easter (Divine Mercy Sunday) in Year A – and indeed across all three years. It is chosen deliberately to link the Resurrection to Old Testament salvation history. The “rejected stone” is fulfilled in Christ’s crucifixion and vindication (quoted in Matthew 21:42, Acts 4:11, and 1 Peter 2:7), while “this is the day” celebrates Easter itself as the new exodus. The emphasis on enduring mercy resonates powerfully with the Gospel (John 20:19–31), where the risen Jesus offers peace, forgiveness, and mercy to doubting Thomas and the fearful disciples. Thus the psalm bridges Jewish festival joy with Christian Easter faith, inviting the assembly to rejoice in God’s victory over death and His unending mercy.