Rezin
Two men named Rezin appear in scripture: a king of Syria whose alliance with Pekah of Israel pressed Judah in the days of Ahaz, and a temple servant whose descendants returned from Babylonian exile.
The King of Syria
Rezin enters the narrative as one of two adversaries Yahweh begins to send against Judah late in Jotham's reign: "In those days Yahweh began to send against Judah, Rezin the king of Syria, and Pekah the son of Remaliah" (2Ki 15:37). The pressure intensifies under Jotham's son Ahaz, when "Rezin king of Syria and Pekah son of Remaliah king of Israel came up to Jerusalem to war: and they besieged Ahaz, but could not overcome him" (2Ki 16:5). The siege fails to take the city, but Rezin uses the campaign to recover Edomite territory: "At that time Rezin king of Syria recovered Elath to Syria, and drove the Jews from Elath; and the Edomites came to Elath, and dwelt there, to this day" (2Ki 16:6).
Ahaz responds not by trusting Yahweh but by buying Assyrian intervention. He "sent messengers to Tiglath-pileser king of Assyria, saying, I am your slave and your son: come up, and save me out of the hand of the king of Syria, and out of the hand of the king of Israel" (2Ki 16:7), stripping the silver and gold from the temple and the royal treasury as tribute (2Ki 16:8). Tiglath-pileser obliges, and Rezin's career ends sharply: "the king of Assyria went up against Damascus, and took it, and carried [the people of] it captive to Kir, and slew Rezin" (2Ki 16:9).
The Prophecy Against the Confederacy
Isaiah's oracle to Ahaz reframes the same crisis. Word reaches Jerusalem that "Syria is confederate with Ephraim. And his heart trembled, and the heart of his people, as the trees of the forest tremble with the wind" (Is 7:2). Yahweh sends Isaiah with his son Shear-jashub to meet the king "at the end of the conduit of the upper pool, in the highway of the fuller's field" (Is 7:3) and to deliver this charge: "Take heed, and be quiet; don't be afraid, neither let your heart be faint, because of these two tails of smoking firebrands, for the fierce anger of Rezin and Syria, and of the son of Remaliah" (Is 7:4). The plot of the two kings — to "make a breach" in Judah and "set up a king in the midst of it, even the son of Tabeel" (Is 7:6) — is dismissed: "thus says the Sovereign Yahweh, It will not stand, neither will it come to pass" (Is 7:7).
The structure of the dismissal pins Rezin to his proper, limited place: "For the head of Syria is Damascus, and the head of Damascus is Rezin; and within threescore and five years will Ephraim be broken in pieces, so that it will not be a people: and the head of Ephraim is Samaria, and the head of Samaria is Remaliah's son. If you⁺ will not believe, surely you⁺ will not be established" (Is 7:8-9).
The prophecy continues into chapter 8. Before Isaiah's child is old enough to speak, "the riches of Damascus and the spoil of Samaria will be carried away before the king of Assyria" (Is 8:4). Because the people "have refused the waters of Shiloah that go softly, and rejoice in Rezin and Remaliah's son" (Is 8:6), Yahweh declares that "the Lord brings up on them the waters of the River, strong and many, [even] the king of Assyria and all his glory" (Is 8:7), a flood that "will sweep onward into Judah; it will overflow and pass through; it will reach even to the neck" (Is 8:8). Later in the same sequence the verdict is repeated: "Therefore Yahweh will set up on high against him the adversaries of Rezin, and will stir up his enemies" (Is 9:11).
Sons of Rezin Among the Returned Exiles
A second Rezin appears in the registers of those who came back from Babylon. Among the temple servants ("Nethinim") listed in Ezra's roster are "the sons of Rezin, the sons of Nekoda, the sons of Gazzam" (Ezr 2:48). Nehemiah's parallel list places the family in the same group: "the sons of Reaiah, the sons of Rezin, the sons of Nekoda" (Ne 7:50). Nothing further is recorded of this Rezin or his descendants beyond the bare entry in the post-exilic genealogies.