John Wesley on Titus 1:15

To the pure - Those whose hearts are purified by faith this we allow. All things are pure - All kinds of meat; the Mosaic distinction between clean and unclean meats being now taken away. But to the defiled and unbelieving nothing is pure - The apostle joins defiled and unbelieving, to intimate that nothing can be clean without a true faith: for both the understanding and conscience, those leading powers of the soul, are polluted; consequently, so is the man and all he does.