Could you please explain how these verses show that there are some who seek God? I don't see it.
I believe Van is speaking of the parable of the sower in Matthew 13. The seed cast on stoney ground and thorny ground believed for a while, but did not persevere.
I disagree with Van's interpretation because anyone who believes is saved, I believe this parable is speaking of producing fruit, not salvation, but that is beside the point. These persons at least for a while were seeking to enter heaven.
A more clear verse Van quotes is Matthew 23:13;
Mat 23:13 But woe unto you, scribes and Pharisees, hypocrites! for ye shut up the kingdom of heaven against men: for ye neither go in yourselves,
neither suffer ye them that are entering to go in.
Jesus said the Pharisees were preventing men who would enter heaven from going in. So, these persons were seeking God and seeking to enter heaven, otherwise it could not be said the Pharisees were preventing them.
And just because scripture says no man seeks God, this does not prove they are unable to seek God.
If I were to say, "None of my neighbors ever goes to church, no, not one" would you understand that to mean they are utterly unable to go to church? NO, no one would get that understanding from my statement, but that is exactly what Calvinists read into scripture. Saying no one seeks God is not saying no one is ABLE to seek God, that is a Calvinist assumption.
The story of the Philipian jailer easily proves man can seek God, he burst in and asked Paul and Silas how he might be saved. He could not possibly have been regenerated, because he had not yet believed, he did not even know he had to believe to be saved when he burst in.
So, the story of the Philipian jailer proves unregenerate men can seek God.