Vayikra: Speaking Close By

From where do we learn that one should not yell to his friend from a distance but rather approach him and talk to him from close by, or call him to come?

The Torah says: "He called to Moshe, and Hashem spoke to him" (Vayikra 1:1).  Although King David says: "The voice of Hashem is in power" (Tehillim 29:4) and there is no problem for Hashem to speak from a distance, He teaches us proper conduct here that one should speak to another person close by.

This is basic etiquette.  One should not bother others by speaking loudly with his friend.  One should also not speak loudly on a cellphone, forcing everyone around him to hear his personal conversation.

Proper character traits must precede Torah learning.