When Catholics (and Orthodox Christians and most historic Protestant traditions) claim that Mary was a virgin before the birth ("virginitas ante partum") they mean that Mary conceived Jesus without sexual intercourse, the conception was by the Holy Spirit.
In Jer. 22:24—30 a curse is pronounced upon this former king of Judah. There it is predicted that none of his seed should prosper sitting upon David's throne. Had the Lord been the natural son of Joseph, who was descended from Jeconiah, He could never reign in power and righteousness because of the curse. But Christ came through Mary's line, not Joseph's. As the adopted son of Joseph, the curse upon Jeconiah's seed did not affect Him.
When Catholics (and Orthodox Christians and most historic Protestant traditions) claim that Mary was a virgin before the birth ("virginitas ante partum") they mean that Mary conceived Jesus without sexual intercourse, the conception was by the Holy Spirit.
That is of course nonsense.
Possibly, there had to be a runtime patch:
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In Jer. 22:24—30 a curse is pronounced upon this former king of Judah. There it is predicted that none of his seed should prosper sitting upon David's throne. Had the Lord been the natural son of Joseph, who was descended from Jeconiah, He could never reign in power and righteousness because of the curse. But Christ came through Mary's line, not Joseph's. As the adopted son of Joseph, the curse upon Jeconiah's seed did not affect Him.
-- Scofield NIV, Matthew 1:11, note 2