Preaching: Qualities of a Preacher

                                                                  Q. Srila Prabhupada said 'preaching is the essence', what does this mean? What are the qualifications of the preacher? Are performing nagar sankirtan and book distribution a kind of preaching? What are the levels in preaching?

                                                                  Q. In one of your lecture/discussion, where you are speaking about preaching or sharing Krishna consciousness with other people, you say something like, ''... if the door isn't open, don't try to go in.'

                                                                  Q. 1. One of the nama aparadhas (offenses against the holy name) is to preach to a non believer. Would you please elaborate on this. It's confusing me as devotees many times preach to a non believer.