John Piper gave this plea in his 2008 message at Together for the Gospel:

My desire and prayer for you is that your life and ministry have a radical flavor. The flavor of risk, sacrifice, love, simplicity, joy, freedom, and precarious adventure.

In 1939, Howard Guinness, one of the early founders of the International Fellowship of Evangelical Students, wrote a little book called Sacrifice. He was trying to do then what I am trying to do now. He wrote,

Where are the young men and women of this generation who will hold their lives cheap, and be faithful even unto death, who will lose their lives for Christ’s, flinging them away for love of him? Where are those who will live dangerously, and be reckless in this service? Where are the men of prayer? Where are the men who count God’s Word of more importance to them than their daily food? Where are the men who, like Moses of old, commune with God face to face as a man speaks with his friend? Where are God’s men in this day of God’s power?

Indeed, where are the pastors who say with the apostle Paul, “I do not account my life of any value nor as precious to myself, if only I may finish my course and the ministry that I received from the Lord Jesus, to testify to the gospel of the grace of God” (Acts 20:24)?

Where are the pastors who say with Joab to his brother Abishai, when surrounded by Syrians and Ammonites, “Be of good courage, and let us play the man for our people, and for the cities of our God, and may the Lord do what seems good to him” (2 Samuel 10:12)?

Where are the young women—single and married—who say with Esther, when the life of her people hung in the balance and Mordecai asked her to risk her life, “I will go to the king, though it is against the law, and if I perish, I perish” (Esther 4:16)?

Excerpted from How the Supremacy of Christ Creates Radical Christian Sacrifice (2008).

Closely tied to this plea is the message delivered by David Platt at the most recent T4G conference, "Divine Sovereignty: The Fuel of Death-Defying Missions." After hearing the message, Pastor John tweeted: “This may have been the most powerful missions message I've ever heard. I needed to be quiet with God.” That message is now online (audio, video).