Inflated ideas, like new cloth, will shrink in the wash

Once again, therefore, I beg all Christians, especially the pastors and preachers, not to try too soon to be doctors of theology and to imagine that they know it all. Inflated ideas, like new cloth, will shrink in the wash. Rather, let all Christians exercise themselves daily in the [basics] and put it into practice constantly. Let them guard themselves with greatest care and diligence against the poisonous infection of false security or self-delusions. Let them continue steadily reading, teaching, learning, thinking, and reflecting...

If they show such diligence, I can promise them - and they themselves will experience - that they will reap a harvest and that God will make fine persons of them, persons who in time will make the excellent confession that the longer they use the Catechism, the less they know of it and the more they have to learn. Then, because they are hungry and thirsty for the Word...[that which now] they do not even care to smell, will first begin to taste really good to them. (Martin Luther, The Preface to the Larger Catechism)