William Perkins in his little book entitled, The Calling of the Ministry (Banner of Truth, Carlisle, PA: 2002), gives a compelling argument for why pastors must preach the Word of God. Here he employs the word "angel" to mean "messenger," which in the Greek language is its basic meaning.
"You must understand your duty: prophets and ministers are angels; that is the very nature of their calling. Therefore, you must preach God's Word, as God's Word, and deliver it just as you received it. Angels, ambassadors, and messengers do not carry their own message, but the message of the lords and masters who sent them. Similarly, ministers carry the message of the Lord of hosts, and are therefore bound to deliver is as the Lord's , not as their own" (85, emphasis mine).
If Perkins is right, and I think he is, then the "Doctor Phil with Bible verses" method seems a great danger to me. Instead, we ought to heed the simple and emphatic words of Paul to Timothy,
"I charge you in the presence of God and of Christ Jesus, who is to judge the living and the dead, and by his appearing and his kingdom: preach the word; be ready in season and out of season; reprove, rebuke, and exhort, with complete patience and teaching. For the time is coming when people will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions, and will turn away from listening to the truth and wander off into myths. As for you, always be sober-minded, endure suffering, do the work of an evangelist, fulfill your ministry." (2 Timothy 4:1-5)