William Burkitt on Romans 16:19

As if the apostle had said, "I do not accuse you, but advise and warn you only; I acknowledge that you the Christians at Rome are famous for your obedience to the apostolical doctrine, and that you walk in faith and love, in unity and concord, to the credit of the gospel, and the honour of your holy religion. But I would have you know, that you are not wholly out of danger of being infected by those judaizers; I wish you therefore wisdom to escape their snares. The Lord make you wise as well as zealous, that you may discern that which is good, and decline that which is evil."

Learn hence, That the holiest, best, and wisest of Christians, must not look upon themselves as secure from the snares of seducers, but stand in need of all the cautions and warnings, of all the advice and counsel, of their spiritual guides, in order to their principles, and the contagion of their example.