Except that believing in Jesus as your Savior sounds a lot like the people who call him "Lord, Lord" who might yet get a nasty surprise. I don't see this as a warning that we should constantly be afraid of whether we have "done enough", as if life is some kind of test where there's no idea of what the pass mark might be or a credible threat that the time I'm spending right now typing on a message board and drinking coffee will suddenly count against me because I could have been standing outside waving a sign saying "Jesus Loves You" at passing traffic or some such.
I think the discussion in this thread alone shows the whole balance between law and grace, between works and faith and so on. As James said, faith without works is dead. If we claim to love God but that love isn't expressed to our neighbors it might reasonably be asked whether we love God at all. Jesus himself said that if we love him we should obey his commandments, and also said the first two commandments were "love God, love each other". If we notionally call Jesus "Lord" but then act as if he is not lord of anything much, we shouldn't be surprised if he says "I never knew you". The trouble is that the warning he gave sounds like at least some of the people who will get that nasty surprise will actually be surprised. We could discuss whether they are the ones who assume they are saved because they went to church every week and their uncle was in the choir, or because they were born in America and therefore think they get a free ticket to heaven, or went forward "to accept Christ" at some event they went to as a teenager before spending their life living as if there was no God - maybe all of those groups will be in for a shock. Combining the things Jesus said, maybe the people who notionally accept the gold coin from their master but then just bury it rather than doing anything useful with it are the ones told "I never knew you".