"This is my blood of the new testament, which is shed for many for the remission of sins"–Matthew 26:28
In an endeavor to explain more plainly the death of the Lord Jesus Christ, and what He accomplished, theologians coined the term 'limited atonement,' in the 17th century. While some may not like the term 'limited' to describe the sacrificial death of the Lord Jesus, nevertheless, we must clearly embrace the truth of it, as revealed in scripture, if we claim to know and believe the Gospel.
If you believe, as many professors do today, that the Lord Jesus actually laid down his life as atonement for every single person in the world, then you limit the atonement in its power to save. Why? Because not all are delivered from guilt and therefore this would leave you with a christ who is less than effectual. An atonement that does not atone is no atonement at all.
The scriptures however reveal an atonement that is unlimited in its power to save, but limited in its design as to who God intended to save by it. In other words, as stated by our Lord Himself, His blood was shed 'for many for the remission of sins.' It is true that Christ died for MANY, a number that no man can number, Revelation 7:9. Yet, this many is limited to AS MANY as the Lord has ordained to believe, Acts 13:48 and AS MANY as the Lord God shall call, Acts 2:39. In Romans 5:15 they are called 'THE MANY,' with a definite article in the original.
The many, for whom He shed His blood, enjoy the blessing of the remission of their sin, because He shed His blood FOR them. That little word FOR sums up the whole Gospel; an effectual atonement by an effectual Substitute. Why is remission of sins the effect of Christ's death? It is because, by His death, He fulfilled all of the necessary requirements to satisfy the Holy Father for the sins of His people. Did He finish the work? Yes, He did! Read Hebrews 1: 3.
The atonement of Jesus Christ is as infinite as God Himself. If God were to add to the number of elect one more sinner, Christ would not have to come and suffer again for that one, Hebrews 10:12. However since the number is sealed from before the foundation of the world, and Christ's death is limited to the number that God the Father has chosen, those who believe on Him, by God's grace, rest in a Savior who saves, an atonement that atones, and a Redeemer who actually redeems!