This is the Gosple - Cancelling our Debt!

Col 2:13-14 And you, who were dead in your trespasses ... God made alive together with him, having forgiven us all our trespasses, by canceling the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross.

A titulus was a sign hung above a crucified person that explained that persons crime. In Jesus' case this said, "King of the Jews." But God also placed a titulus above the cross of Christ and that sign said, "the record of debt with its legal demands" explaining that everyone whom Christ died are now no longer sinners. How so, you'll ask. In this way, all of the sins of everyone Christ died for where a debt that Christ paid for, therefore no more debt for those people. He set this record of debt aside (removed it) by "nailing it to the cross."
This brings us to one of the strongest understandings of limited (or I prefer Particular) atonement. As False Teachers must deny this by saying either: Everyone is saved because Christ atoned for the sins of every human being (a heresy known as Universalism) or that Christ died for every sin except the sin of unbelief. Which is why they have to challenge us to "grasp" or "earn" or "work for" our salvation because God only cancelled 99% of the debt and we have to cancel the last little bit. Mainly this is exemplified by a Multi-step path to attaining salvation.
Whether you're taught to earn salvation in any of a hundred ways: make a free-will decision (which you cant, simply because the will is not free), pray a special prayer (that magically removes your sins), walk an aisle (thankfully works righteousness is easy in lazy America), fasting, travel to a holy site, convert a sinner (this is the pyramid scheme system - convince 6 others to make a false profession of faith and you'll be saved as well), confess every sin (which you cant because you don't know 2/3rds of them), get baptized (God only loves wet people and if your not wet then even if you're a genuine believer God doesn't want you, you haven't done enough for Him- Satire), read the whole Bible, volunteer to work in the nursery (many churches imply this simply because otherwise no one would volunteer in the nursery), tithe (if you don't give your 10% gift, why would God want to gift you Eternal life) or many conservative churches will say not do this but their good works are all - we don't do this: don't drink, don't watch secular movies, don't listen to secular music, don't dance - I've been in the Church for 25 years so I could do this all day I've seen all the traps of works righteousness.  - just know that 100 verses state salvation is by genuine faith in the Biblical Christ and His work done for you. If you add to or take away from that then simply you don't understand Salvation.