Well, lots of people PROFESS to believe in Christ and Jesus said that there would be those who on that day say, *Lord, Lord, didn’t we........(fill in the blank) in your name?* and He will sent them off with a *I never knew you*.
Those who give the impression that you can accept Jesus and then live like the devil are those who give a bad name to the Scriptural promises of the security of the believers.
Wolves in sheep’s clothing are still wolves and were never saved to begin with.
The hard part is that there are some who are weak and just continually struggle with sin.
But the flaunting your sin and spitting in the face of God kind of attitude that is described by those who would attack the security of the believer is not representative of the believer.
So, yes, all believers ARE secure.
But not all who profess Christ are because not all who profess Christ are saved.
Ain't that the truth. There are millions who think they are Christians, but are actually enemies of God, who will wake up in the fires of Hell, and say, didn't we do many good works in your name?
These people never lost their salvation. They never had it to begin with. Unregenerate sinners from the start. They need to get their act together, and if they don't, that's on them.