Reformed Baptists affirm the traditional reading of Isaiah 7:14 as a Messianic prophecy fulfilled in the virgin birth of Jesus. The Hebrew עַלְמָה ('almah') is understood as 'virgin,' and the prophecy signifies a miraculous birth—the Messiah born of a virgin without male human participation. This reading is foundational to Reformed Baptist Christology and connects to the broader claim that Jesus is the promised Messiah of Israel.

The virgin birth is affirmed in the 1689 London Baptist Confession as a marker of Christ's uniqueness and his sinless nature. The doctrine emphasizes that Christ enters the human race through a supernatural act of God, distinct from ordinary human generation. This affirmation is integral to the Reformed doctrine of Christ's two natures and the integrity of his redemptive work.