The physical voice we use in prayer need not be great nor startling; even should we not lift up any great cry or shout, God will yet hear us.
When anyone prays, the angels that minister to God and watch over mankind gather round about him and join with him in prayer.
The discussion of prayer is so great that it requires the Father to reveal it, His firstborn Word to teach it, and the Spirit to enable us to think and speak rightly of so great a subject.