Further illustrations might be adduced of metaphors and lines of arguments in the writings of St. Paul which appear to be derived from the Roman law. St. Paul is perhaps of all writers, either ancient or modern, the most difficult to understand. It cannot be that his obscurity is deliberate. It is due chiefly, no doubt, to our ignorance of the intellectual atmosphere of the age in which he lived. It is not suggested that a study of the Roman law as it existed in the first century will afford an explanation of all the perplexing passages in which the Pauline Epistles abound; but it is certain that no satisfactory commentary upon these Epistles will ever be produced except by an author who, in addition to other qualifications, is a thorough master of the history of civil jurisprudence.
from pager 36-37, St. Paul and the Roman Law