Tonight's questions

Feel free to post me any suggestions to answers to these. I must though admit, I am not sure this will be the most applicable or insightful study. 

1.  How would you prove that murmuring is a sin?

2.  In what circumstances are we tempted to murmur?

3.  Does murmuring reveal any other sins that might be present in our lives?

4.  What effect, if any, does murmuring have on those around us?

5.  How can we prevent murmuring?