2 Samuel 22:50 → Deuteronomy 32:43

At the doxological climax of his victory song, David vows, "Therefore I will praise You, O LORD, among the nations (בַּגּוֹיִם); I will sing praises to Your name" (2 Sam 22:50 = Ps 18:49) — having just been made "head of nations" (v.44), the anointed king resolves to lift Yahweh's praise in the midst of the Gentiles, not only within Israel. This deliberately picks up the trajectory set at the close of the Song of Moses, where Moses summons, "Rejoice, O nations, with His people" (Deut 32:43) — the Torah's own anticipation that the gôyim will one day join Israel's worship of the LORD. The link is not a verbal quotation (David does not cite Moses' line) but a genuine Echo: the shared frame is the nations / גּוֹיִם drawn into the doxology of the one true God, in a context of His vindicating victory. The operative method is Longitudinal Theme — the canon-wide Gentile-praise / one-people-of-God thread that runs Mosaic-Song → Davidic-doxology → prophetic-and-Psalmic widening (Ps 117:1; Isa 11:10) — and not typology, since neither text sets up a person or institution that escalates into an antitype; it is a thematic-doxological current, not a type. The two texts are not arbitrarily paired: Paul welds them together in the Romans 15:9-12 catena, citing 2 Sam 22:50 / Ps 18:49 at Rom 15:9 and Deut 32:43 at Rom 15:10, so that the Davidic warrant and the Mosaic warrant stand side by side as twin OT testimonies to Gentile inclusion. The road to Christ runs through that catena: the praising king of 2 Samuel 22 is the type-bearing forefather of great David's greater Son, whose resurrection-enthronement (Rom 15:12, citing Isa 11:10) finally throws open Israel's worship to all peoples — so that the Gentiles now "glorify God for His mercy." The telos is not that Gentiles are merely permitted to sing, but that in Christ the nations are given a God so glorious and a mercy so vast that praise becomes their joy — the veil lifted (2 Cor 3:18), the whole world summoned not to duty but to delight, "rejoice, O nations," because the Object of that praise is at last seen as supremely desirable.