Obviously, a man leading a public prayer should pray loudly enough that those who are assembled with him and on whose behalf he is praying can adequately hear the prayer. How else could they acknowledge the appropriateness of and express their agreement with the prayer by saying “Amen”? A pray would be indiscernible not only if it were spoken in a language the hearer did not understand, but also if it were spoken quietly enough that the hearer could not make out the words (1 Corinthians 14:16). Certainly, lacking a public address system, one would need to speak more loudly than if a public address system were available.
However, purposely making a spectacle or unnecessary show while praying by shouting (praying much more loudly than required for the circumstances) is another matter. Scribes in Jesus’ day were condemned by our Lord for their showmanship while making public prayers; maybe loud, their prayers were also unnecessarily “long.”
Beware of the scribes, which desire to walk in long robes, and love greetings in the markets, and the highest seats in the synagogues, and the chief rooms at feasts; Which devour widows’ houses, and for a shew make long prayers: the same shall receive greater damnation.” (Luke 20:46-47)
One should pray loudly enough and for the right purpose. More than that is not authorized by Holy Scripture.
