8 rules for preachers from Luther

Paul Levy
I've really enjoyed James M.Kittelson's ''Luther the Reformer'' which sadly is out of print in the UK. In it he gives Luther's 8 rules for preachers (page 249/250)
''First , a good preacher should be able to teach well, correctly and in an orderly fashion.
Second, he should have a good head on his shoulders.
Third, he should be eloquent.
Fourth, he should have a good voice.
Fifth, he should have a good memory.
Sixth, he should know when to stop.
Seventh, he should be constant and diligent about his affairs.
Eighth, he should invest body and life, possessions and honor in it.
Ninth, he should be willing to let everyone vex and hack away at him.''