I’ve often said this about Luther: “Martin Luther is only helpful if he brings us the Word and points to Christ. Which he does (most of the time).” Luther says the same thing about the teachers of the church (commenting on Genesis 25:26):
Examples of this kind teach us that one should not believe any human being, no matter how saintly he may be, but must pay attention to Him who calls and to His Word. But one should not study the Word for only a year or two, for the Word of God is a boundless subject. Our adversaries exclaim: “Ambrose, Augustine taught this or that!” But they are of no importance to us unless they bring the voice of Christ.
Whoever of them has the Word and that voice in greater clarity, I would rather follow him than I would want to follow Augustine or anyone else. Thus Augustine teaches Holy Scripture more clearly and discusses it more skillfully than Ambrose. Therefore it is more profitable to read him than Ambrose.
But in regard to all let us always hold fast to the following words: “Thy Word is a lamp to my feet and a light to my path” (Ps. 119:105); and 2 Peter 1:19 states: “We have the prophetic Word made more sure. You will do well to pay attention to this as to a lamp shining in a dark place, until the day dawns and the morning star rises in your hearts.”
(Luther’s Works 4:377-378)
When reading Luther, I believe that a good approach is that taken by the “more noble” Bereans (Acts 17:11), who were very open to the message brought by Paul and Silas but did not uncritically swallow all that they had heard. Rather, they examined the Scriptures earnestly to see whether what they were told was true.
It was a policy of “trust but verify” in apostolic times. And it’s useful today when any Christian author serves a meal consisting of the Word predigested rather much and smothered in his own special sauce.