"Even Roman Catholics believe that salvation is by grace... that is not the issue...and never has been ... the issue is that salvation is by grace ALONE. In other words, Jesus is not only necessary but sufficient to save us to the uttermost."
Sadly, even many Protestants claim they believe in "grace alone" in their confession but deny it with their theology. In many cases, such claims are largely meaningless and without substance. For example, if you believe a man can lose his salvation then, by definition, you already affirm that YOU must maintain your own just standing before God. Christ may be necessary in the process but He only partly helps - or maybe even contributes a large part. But "part" is not "all" of Christ, or else loss of salvation would be an impossible supposition ... but because there is something you could do to lose it, you must, therefore, maintain it. With the help of grace yes... but such grace, by itself, is not enough if you can do something to lose it ... it is grace plus my effort. That is not "All of Christ" or "Christ alone" by any definition.