In the discussion as to why Jesus spoke aloud the "Lazarus, come out",
I'm surprised that no one has noticed the verse immediately preceeding.

Jn 12:41  "Father, I thank you for listening to me, though I knew that
you always listen to me.  But I have said this for the sake of the
people that are standing around me that they may believe that you have
made my your messenger."  (Goodspeed translation)

My guess is that the "Lazarus, come out!" was also for the sake of the
crowd.