What is a good topic sentence that will hook my readers on this this topic: "Martin Luther a hero or a zero"? This has to do with Martin Luther...

I believe that you are asking for advice on how to write a good "attention getting" statement to a paper or essay.  An attention getting statement is the first sentence that is written, and it is specifically designed to hook your reader's attention.  A hooked reader will keep on reading, which is what you want.  

Without knowing who your intended audience is, I can't write out a perfect "attention getter" for you.  You know your audience better than I do.  But I can offer strategies for how to write a good attention getting sentence.  

In my writing and speech classes, I teach five different types of attention getters.  

1. Make a bold statement.  Your "Martin Luther hero or zero" is on the right track for this kind of attention getter.  Most Christians have high esteem for Luther and his work toward creating the modern church.  So even mentioning that he could be considered a zero will grab a reader's attention.  The point with a bold statement is that you are stating a strong opinion about something controversial.  You could say something like "Martin Luther is the most overrated religious figure in history." A word of caution though.  I wouldn't make your bold statement something that is likely to run counter to reader opinion.  You don't want to put your reader on the defensive right from the beginning.  That makes your audience antagonistic to your writing.  Save your counter arguments for a bit later.  


2. Use a quote.  Because you have said that you are going to write about Martin Luther, use a quote from Martin Luther.  It doesn't even have to be from his 95 theses.  Readers automatically assume that they should pay closer attention to quoted material, because they think it must be worthwhile if the author (you) is quoting another writer's words.  


3. Ask a question.  Questions do a nice job of engaging readers, because questions always beg an answer.  "Was Martin Luther really as influential as the church gives him credit for?" If you can get your reader thinking about your question and trying to answer it in their own mind by the end of the first sentence, you have a hooked reader.  I find a lot of students like to use the question technique, because it's easy to write and start with.  If you're like a lot of students, the hardest part is simply starting to write. 


4. Use a definition.  This is my least favorite attention getter.  I feel it is dry and uninspiring, but it does work in the right situation.  It works for the same reason that a quote works.  Readers assume that the definition is key to understanding what is next, so they focus closely on the detail of the definition.  


5. Tell an anecdote.  This can be easily incorporated into a speech, but it doesn't necessarily always work with written papers.  I believe that you could make it work with Martin Luther.  I could easily see you narrating over the course of 6-8 sentences Martin Luther's actions and steps to the church door that he nailed his 95 theses to.  That kind of start would really get readers in the proper mind set to analyze what the impact of Luther's actions were.  

I hope this helps.  Good luck!