Scripture is not of private interpretation but … there is one sure interpretation particularly of those passages in which dogmas or articles of faith are treated as established on their own foundation, when Scripture explains itself by clear interpretation either in that particular passage or in other passages in which the same dogma is repeated. (M. Chemnitz, ‘The Lord’s Supper’ (CPH, 1979), 91)

So much for the Protestant ‘insight’ that allowed every man to interpret the Scriptures for himself (à la e.g. A.G. Dickens), or that the true magisterium is the inner witness of the Holy Spirit (à la [allegedly] Calvin).

“It often happens that if the Scriptures prescribe something which is contary to the practice of those who hear it, they treat is as a figurative expression. Likewise, if some erroneous notion has gotten into our minds first, regardless of what Scripture has asserted, men will think it is figurative.”

St. Augustine, De doctrina Christiana 3.10, quoted in Martin Chemnitz, The Lord’s Supper (CPH, 1979), p. 76.