The verse is there for Martin to read rather than deny. There we entering so they had some spiritual ability. Surely Martin is not saying people can be "entering" without any spiritual ability. Your guess is as good as mine.
Matthew 23:13.
'But woe to you, scribes and Pharisees, hypocrites! For you shut up the kingdom of heaven against men; for you neither go in yourselves, nor do you allow those who are entering to go in.'
Van's claim is that the people described as entering were unregenerate; you will have to ask him why he thinks that. I have asked Van whether he thinks that the people described actually entered or not, but he will not tell us because whatever he says, refutes his claim as I will show. [I have actually posted something very similar to what follows several times and I apologize to those who have read it before, but Van keeps trotting his nonsense out, so what can I do?]
If the scribes and Pharisees actually prevented these people from entering the kingdom, then unregenerate people do not enter the kingdom QED. If they did enter, then the Pharisees couldn't stop them and there's no reason to suppose that they were unregenerate. So either way, Van is snookered.
What is the truth? Well, does something not being allowed prevent it from happening? Murder is not allowed in the UK and USA. There are laws against it. Does that stop it happening? Alas, no.
In Saudi Arabia, no Saudi citizen is allowed to leave Islam on pain of death, yet we know that there are many secret Saudi believers. So something not being allowed doesn't stop it from happening. In the words of the song:
Mama don't allow no guitar-picking round here,
Mama don't allow no guitar-picking round here;
But we don't care what Mama don't allow;
Gonna play our guitars any old how.
Mama don't allow no guitar-picking round here.
So in Matt. 23:13, the S & Ps may not allow folk to enter the kingdom, but still they enter.
"I will build My church and the gates of hades shall not prevail against it" If you want to see how this works out in practice, then read John 9. The Pharisees did everything possible to keep the man born blind from following Christ, to the point of excommunicating him (v.34), but he still ended up in the kingdom (v.38).