At the end of his letter to the Ephesians, the imprisoned Apostle Paul writes and requests pray for his ministry of the Word — “ praying at all times in the Spirit, with all prayer and supplication. To that end keep alert with all perseverance, making supplication for all the saints,  and also for me, that words may be given to me in opening my mouth boldly to proclaim the mystery of the gospel,  for which I am an ambassador in chains, that I may declare it boldly, as I ought to speak. (Ephesians 6:18-20, ESV, emphasis added).
Commenting on this, the late John R. W. Stott wrote* about the importance of clear and bold preaching —
“Clarity and courage remain two of the most crucial characteristics of authentic Christian preaching. For they relate to the content of the message preached and to the style of its presentation. Some preachers have the gift of lucid teaching, but their sermons lack solid content; their substance has become diluted by fear. Others are bold as lions. They fear nobody, and omit nothing. But what they say is confused and confusing. Clarity without courage is like sunshine in the desert — plenty of light but nothing worth looking at. Courage without clarity is like a beautiful landscape at night time — plenty to see, but no light by which to enjoy it. What is needed in the pulpits of the world today is a combination of clarity and courage . . . Paul asked for the Ephesians to pray that these might be given to him, for he recognized them as gifts of God. We should join them in prayer for the pastors and preachers of the contemporary church.”
*from The Message of Ephesians, (The Bible Speaks Today series); IVP, 1979; page 286.