Limited Atonement

 My Particular beliefs is that Christ death on the cross is the sole difference maker between saved and not saved. By that I mean that either Christ died for one and so thereby won one's salvation or he did not.

The Bible talks about the blood of Christ. By it we are justified (Romans 5:9), we are accepted (Eph 1:7), with his own blood he purchased the congregation - Acts 20:28. We overcome the world by the blood (1 John 5, Revelation 12:11).

There are other verses. For me preaching a definite and accomplished redemption is what the gospel is. A man or woman (in keeping with the times) either accepts this or they do not. They either assent to the saving message of what Christ did or they believe something else is what saves.
Romans 6 I think is referring to the Gospel by which the elect were united to Christ death, burial, and resurrection which is the basis or motivation for the Apostle Paul to give us the law as a "Rule of Life" and not as a "Covenant of Works" to not continue in sin.

Now the question arises, what is the sin in which Paul here implores Christians not to continue in? I think Paul is talking about the sin of unbelief. Notice he does not say shall we continue in SINS plural but rather shall we continue in SIN singular. The sin in which he writes against is the sin of not reckoning, not knowing, and not believing the gospel truth. Of course, believers can only do this because of what Christ did for them.