Some pastors and preachers are lazy and no good. … They do not pray; they do not study; they do not read; they do not search the Scripture. …
[T]he [pastoral] call is: Watch, study, attend to reading. In truth, you cannot read too much in Scripture; and what you read you cannot read too carefully, and what you read carefully you cannot understand too well, and what you understand well you cannot teach too well, and what you teach well you cannot live too well.
Therefore, dear sirs and brethren, pastors and preachers, pray, read, study, be diligent. Truly, this evil, shameful time is not the season for being lazy, for sleeping and snoring. Use the gift that has been entrusted to you, and reveal the mystery of Christ.
–Martin Luther, What Luther Says: An Anthology, comp. Ewald M. Plass (St. Louis: Concordia Publishing House, 1959), entry no. 3547, 1110.