Then you call on the name of your god, and I will call on the name of the Lord. The god who answers by fire—he is God.” Then all the people said, “What you say is good.”
Elijah said to the prophets of Baal, “Choose one of the bulls and prepare it first, since there are so many of you. Call on the name of your god, but do not light the fire.” So they took the bull given them and prepared it.
Then they called on the name of Baal from morning till noon. “Baal, answer us!” they shouted. But there was no response; no one answered. And they danced around the altar they had made.
At noon Elijah began to taunt them. “Shout louder!” he said. “Surely he is a god! Perhaps he is deep in thought, or busy, or traveling. Maybe he is sleeping and must be awakened.” So they shouted louder and slashed themselves with swords and spears, as was their custom, until their blood flowed. Midday passed, and they continued their frantic prophesying until the time for the evening sacrifice. But there was no response, no one answered, no one paid attention. (NIV)
I have been in prayer groups where I have prayed my own prayer for a certain situation or person and found that another member of the group prays after me with much the same content but with a much louder voice. Of course this may be just a matter of temperament or a sincere expression of deep passion.
But sometimes it represents a dangerous misunderstanding of faith. It is as if the louder we shout the stronger our faith is shown to be. Or even worse, that unless we are very strident and aggressive and loud we will not be heard. Much like those misguided worshippers of Baal in Old Testament times.
Our God is compassionate, slow to anger and abounding in mercy. He knows our desires and needs before we use words to express them. We don’t have to show off our mighty faith or fervent enthusiasm in order to have him respond. A whisper, or even a sigh, is good enough.
By all means pray loudly if that comes naturally. Just don’t assume that it makes any difference to God. He is neither indifferent or deaf.