Preaching: Importance of Time and Circumstances

                                                                  Q. We are taught to accept Guru as he represents the disciplic line. I've read and heard that guru always speaks without deviation from the previous Acharya in the line. I was wondering about the difference between Sri Madhvacharya and Sri Chaitanya Mahaprabhu. Specifically as it pertains to our line, and the question of authenticity.

                                                                  Q. If Jesus, Mohammed and Buddha were giving a message relevant to a particular time and place, why didn't they give the name Krishna as it would have meant the solution to a lot of problems of today? Just because they didn't, does it mean that their teachings are not valid?