Musings about Unlimited Atonement
There is good support for an unlimited atonement that applies only to those who believe. There is good biblical evidence and theological evidence from other doctrines that support this position.
Jesus died for all mankind but His death only applies to the elect who have received Christ as their savior. This is an unlimited atonement, meaning that Christ died for everyone. The other main position some Christians take is one of limited atonement (or otherwise called particular atonement, meaning that the atonement was specifically for some people). Biblically, the position of unlimited atonement is demonstrated by several statements in Scripture. For the universal extent of this death, Scripture says "He Himself is the propitiation for...[the sins] of the whole world" (1 John 2:2), that God "desires all men to be saved" and Jesus "gave Himself as a ransom for all" (1 Timothy 2:4,6). It is true that the Greek word κοσμος can be used in a way that does not mean everyone without exception, but in most of the passages relevant to this issue there is not sufficient reason to take them this way. Even more powerfully, there are indeed people whom appear to have had a real experience of Christ having purchased them who nonetheless seem to be lost. (2 Peter 2:1) Concerning the necessity of belief, Scripture also says "[God] is the Savior of all men, especially of believers" (1 Timothy 4:10 NASB and that Jesus is "a propitiation in His blood through faith." (Romans 3:25a NASB). More scriptures could be cited in support of these points, but these are sufficient. Theologically, this position is also substantiated by several other doctrines. First, the universal gospel invitation is good theological support to presume that Jesus did die a universal atonement. It would be nonsensical for God to command a universal gospel proclamation when He did not actually die for all being preached to. Second, the infinite nature of Christ's sacrifice also supports a universal atonement. It is somewhat arbitrary to try to theologically limit His atonement for the sake of an overall system when everyone admits His death had unlimited value. Third, the condition of faith for the atonement to apply supports a full atonement that may not apply to everyone. This condition incipient in the very nature of propitiation (see above) is essential to properly demonstrating how a universal atonement is not a travesty of justice by the "double-payment" that is claimed when some people go to hell. The additional consideration with an approach like this a question about what blessings are received by those who are not saved. Regarding the blessings the lost receive, it is not accurate to view their experiences of commons grace as a blessing they receive from the atonement. Instead, it is accurate to say they received no benefits at all, and in fact by their rejection of the atonement, they accrue more judgment to themselves (c.f. Matt. 11:20-24). The atonement blessings are conditioned on the sinner responding right in faith to the conviction of the Spirit (John 16:8-11). Finally, it seems persuasive to me to logically deduce that it makes more sense for God, possessing a holy love and a loving holiness, to purpose first to provide a universal atonement that would then be effectual to a subset of humanity (this is close to the sublapsarian view). In conclusion, there is good support, both biblical and theological, for advocating an unlimited atonement that applies only to those who believe.

