Who was Paul writing the book of Romans to?
Paul wrote the book of Romans to the common, ordinary believer in the pew, not merely to the hierarchy of the church at Rome. He addressed every believer so they would be aware of these things and not remain ignorant of the secret.
Les explains that Paul was not writing only to the church hierarchy in Rome but to the common, ordinary believer sitting in the pew. Every believer needs to know these truths, which is why Les teaches the common people rather than only preachers and seminarians. Paul desired that the brethren not be ignorant of the secret, and ignorance is simply a lack of being taught. This shows God wants all believers to replace ignorance with the wisdom of His Word.
For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.