I think you misunderstand what repentance does. Let me ask you, did repentance stop you from sinning? And if not then aren't you, as well as every Christian in the world, unsaved as well?
Like I said, there's a difference. If I am screwing my girlfriend, and I go to church, and they say "screwing someone you are not married to is sin". Now, I have an option of repenting.... and by repenting I stop doing what I now know is evil and wrong.
If I choose to do what I know is evil and wrong, and yeah I shouldn't be screwing my girlfriend, but I am going to keep doing it.... then I'm the guy Jesus was talking about
"Why do you call me 'Lord Lord' and do not do the things that I tell you?"
On the other hand, if I know that screwing someone I'm not married to is wrong, and go to a small party, and I start talking with a girl, and we end up outside talking, and then she invites me to her car, and somehow I end up at her house and sleeping with her....
Then I wake up the next day... oh no I've sinned. I repent. I tell her I'm not doing that anymore and stop seeing her. I go to church, and pray for forgiveness. Then I don't do that anymore.
Knowing something is wrong, and stumbling into sin, is not the same thing as saying... yes I know sleeping with my girlfriend I'm not married to, is wrong, but I am going to do it anyway.
If you are making a conscious choice to do what is sinful, even if you know it's wrong.... Then you are that guy Jesus was talking about.
"Why do you call me 'Lord Lord' and do not do the things that I tell you?"
Honestly, who did you think he was talking to? People who hear what he said not to do, or to do, and refused to do it.
I'll give you an example from my own life. For various reasons, I got into the habit of lying quite a bit when I was younger. At some point in my Christian life, I realized my 'little white lies' were lies, and sinful and wrong.
I have a policy that now I tell the truth. I've had people complain at me that I am "too truthful" now. Does that mean I never lie? Of course not. Sometime in the heat of the moment, I say something I should not.
But by the grace of G-d in Heaven, that isn't the pattern of my life, and G-d willing those moments where I fail are fewer and fewer, and far between. I've repented of my old ways, and I don't live like that anymore.
And I pray on the name of Jesus that, his statement no longer applies to me.
"Why do you call me 'Lord Lord' and do not do the things that I tell you?"
I don't keep doing what I know is wrong.
If you know what you are doing is wrong, and you keep doing it anyway.... you are that guy.