Go to Jeremiah 22:30.
Thus saith the LORD, Write ye this man childless, a man that shall not prosper in his days: for no man of his seed shall prosper, sitting upon the throne of David, and ruling any more in Judah.
There is a curse on Jeconiah, the king of Judah, that no man of his seed will prosper or sit on the throne of David. Jeconiah, being a king of Judah, is a descendant of David and an ancestor of Jesus. We know Jesus sits on the throne of David, so how does God get around the Blood Curse on Jeconiah?
Well, with a virgin birth, of course. God also arranges for Joseph, who is a direct heir of Jeconiah, to become Jesus’ legal father. Joseph is not, however, related to Jesus by blood.