Some doubted Paul was an apostle but he turns it around and demands proof that they are true Christians. This is the biggest issue for us: eternity is not a thousand years or a million but forever. Christ is in the Christian from the moment they trust and for ever. The King lives in us... unless we fail the test. There are those who think they are going to heaven and are not. We must make sure.
The video of the entire service including recorded Hebron congregational singing can be viewed here.