What does it mean that redemption involves a specific object?

The concept of redemption involving a specific object means that Christ did not redeem the world in a general sense; rather, He purchased a particular people for Himself, known as the elect. This notion is grounded in Ephesians 1:4, where Paul identifies the 'we' as the chosen. Just as someone can buy back what was lost or sold, redemption demands that there be a specific possession lost, which was indeed the case for God's elect who fell under the curse of the law and were separated from Him by sin.