To distinguish between the true and the counterfeit is bring it to the Light of Truth.
"Examine yourselves, whether ye be in the trust; prove your own selves. Know ye not your own selves, how that Yah Shua is in you, except ye be reprobates?"
Most cults teach that simply believing in Jesus is enough. Paul says you must test yourself to make sure He is in you. The difference between accepting the historical Messiah and having Him in you.
The counterfeit says don't worry. Don't study. Don't make sure. Don't listen to him he just lies to his own advantage.
The real says, test yourself, take great pains to ensure accuracy and truth of doctrine, test the spirits, judge all things, be on your guard, make you calling and election sure, beware of dogs...
One more time, as the wolves like Tupper, assert that 2 Cor. 13:5 KJV is Paul's warning, to check to see if you are saved. That is, the most carnal bunch of Christians, should examine themselves, to see if they "passed the test." No, when Paul told them to “examine” themselves, he was only arguing, in defense of his apostleship, which was constantly being questioned-he was confronting his critics,responding to those who would "check him out"/question him/examine him.....
1 Cor. 9 KJV
1 Am I not an apostle? am I not free? have I not seen Jesus Christ our Lord? are not ye my work in the Lord? 2 If I be not an apostle unto others, yet doubtless I am to you: for the seal of mine apostleship are ye in the Lord.
3 Mine answer to them that do examine me is this,
The context of 2 Cor. 13:5 KJV was not doubting the carnal Corinthians' salvation-he always referred to them as "saints." He wrote the passage, because they were questioning his authority/apostleship....
2 Cor. 13 KJV
3
since ye seek a proof of Christ speaking in me, which to you-ward is not weak, but is mighty in you.
You left out the verses that proceed 2 Cor. 13:5 KJV.
Thus, Paul's point is that if they were “in the faith,” it proved the proof that he was an apostle, for he was the one that led them to the Lord Jesus Christ.
1 Cor. 9 KJV
2 If I be not an apostle unto others, yet doubtless I am to you: for the seal of mine apostleship are ye in the Lord.
Thus, since these carnal Corinthians were “in the Lord” and “in the faith,” was the evidence of his apostleship-2 Cor. 13:3 KJV, removing the/their doubt.
That is the context.