From Redemption Accomplished and Applied by John Murray, here is an excerpt from chapter 4 The Extent of the Atonement.
The very nature of Christ's mission and accomplishment is involved in this question. Did Christ come to make the salvation of all men possible, to remove obstacles that stood in the way of salvation, and merely to make provision for salvation? Or did he come to save his people?
Did he come to put all men in a savable state? Or did he come to secure the salvation of all those who were ordained to eternal life?
Did he come to make men redeemable? Or did he come effectually and infallibly to redeem?
The doctrine of the atonement must be radically revised, if as atonement, it applies to those who finally perish as well as those who are heirs of eternal life.