How do we know that Christ's blood was shed specifically for the elect?

The doctrine of particular redemption asserts that Christ laid down His life specifically for His sheep, as indicated in passages like Acts 20:28, where Paul states, 'Feed the church of God, which he hath purchased with his own blood.' This highlights that the blood of Christ was intended to secure the salvation of those whom the Father gave to the Son. In contrast to a general atonement that claims Christ died for every individual, the sovereign grace perspective maintains that His sacrifice effectively redeems and justifies the elect, as emphasized in Ephesians 1:7 where it states that we have redemption through His blood.