Possible Clues:

• Power is an advantage for a boxer or a job for one doing clerical work
• With 47-Across, not change anyone's mind, say
• After pressure get to give sermon
• Harangue
• "You said it!"
• Copper to get hold of address
• Deliver a sermon, say
• Deliver a homily, quietly gaining measure of influence
• Do a pastor's job
• Evangelise quietly about a place of worship