From his “Preface to the German Writings” (1539):
“I want to point out to you a correct way of studying theology… This is the way taught by holy King David (and doubtlessly used also by all the patriarchs and prophets) in the 119th Psalm. There you will find three rules, amply presented throughout the whole Psalm. They are Oratio, Meditatio, Tentatio [prayer, meditation, anguish or “Anfechtung”].
“Firstly, you should know that the holy Scriptures constitute a book which turns the wisdom of all other books into foolishness, because not one teaches about eternal life except this one alone. Therefore you should straightaway despair of your reason and understanding… But kneel down in your little room [Matthew 6:6] and pray to God with real humility and earnestness, that He through His dear Son may give you His Holy Spirit, Who will enlighten you, lead you, and give you understanding.
“Secondly, you should meditate, that is, not only in your heart, but also externally, by actually repeating and comparing oral speech and literal words of the book, reading and rereading them with diligent attention and reflection, so that you may see what the Holy Spirit means by them. And take care that you do not grow weary or think that you have done enough when you have read, heard, and spoken them once or twice, and that you will then have complete understanding. You will never be a particularly good theologian if you do that, for you will be like untimely fruit which falls to the ground before it is half ripe.
“Thirdly, there is tentatio, Anfechtung. This is the touchstone which teaches you not only to know and understand but also to experience how right, how true, how sweet, how lovely, how mighty, how comforting God’s Word is, wisdom beyond all wisdom… For as soon as God’s Word takes root and grows in you, the devil will harry you, and will make a real doctor of you, and by his assaults [the anguish] will teach you to seek and love God’s Word.”