Exodus 9:7 records Pharaoh voluntarily hardening his heart earlier in the same chapter, before God's active hardening here.

Exodus 4:21 foretold God hardening Pharaoh's heart, which is exactly what happens in Exodus 9:12—a direct fulfillment.

Exodus 7:13 is the first instance of Pharaoh's heart hardening, setting the pattern for the repeated hardening seen here.

Exodus 7:14 shows God's own assessment that Pharaoh's heart is hard, preceding the divine hardening action here.

Exodus 10:20 is a later instance of the same divine hardening of Pharaoh's heart, continuing the pattern.

Revelation 16:11 shows people refusing to repent despite plagues — directly parallel to Pharaoh's hardened response after judgments.

Amos 4:10 explicitly recalls the Exodus plagues as a warning to Israel — showing the same stubbornness pattern as Pharaoh's.