It's a misreading of Genesis 12:3
"I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed.”
St. Paul comes out and says that this is a reference to Christ alone in the book of Galatians. Scofield was paid to say that the referent to "in you" was actually the people descended from Abraham rather than the Savior who descended from him according to Christ's humanity
