That means he regards the Bible as his only rule of faith and practice who knows he has been saved by the sacrifice of Jesus Christ on his behalf, his only Mediator, Redeemer, King, Savior and Lord.
Schwertley disagrees. It's the pride of his bio:
Another bit of news is the scandal surrounding Schwertley, including accusations of breaking numerous commandments. More can be found here and here.
But I'm sure his Catholic bashing book is considered to be at the top of the list in Presbyterian circles.
Looks like it's time to add another noodle to the chart of Presbyterian denominations.