"Sola gratia", or "grace alone" is a doctrine that is affirmed by the vast majority of protestant Christianity. But it has been my experience that protestants outside of the reformed traditions only pay lip service to this doctrine. That is, they will affirm sola gratia on the one hand, while emptying the term of all meaning on the other. Case in point:
We believe in salvation by "Grace" plus nothing and minus nothing. The conditions to salvation are repentance and faith in Jesus the Christ:
This statement comes from Covington Seminary's statement of faith. Immediatly, the Calvinist sees a very basic problem. It is here stated that salvation is by grace plus nothing and minus nothing. Leaving the "minus" out, we can put it another way:
Grace + Nothing = Salvation
or
G + N = S
Now, this would be in accordance with Sola Gratia if the statement stopped here. But it doesn't. The statement goes on to say that salvation is conditioned on two other things. That is, two conditions are added to the above formula so that now we have:
Grace + Faith + Repentance = Salvation
or
G + F + R = S
As just stated, the problem is obvious to a Calvinist. The statement started with positing that salvation came by grace plus or minus nothing only to turn around and say that salvation came by grace, repentance, and faith. In the above formulas, nothing (N) cannot be equivalent to faith (F) and repentance (R) because to suggest this would be to deny the reality of faith and repentance in Christian doctrine. Thus, for the Christian, it is one or the other and not both. And while I'm sure that Covington Theological Seminary is a fine institution of Christian learning, someone over there needs some classes in remedial math.