That's Why We Memorize Scripture

From Pipers sermon "How God’s Word Produces Our Work"

"On December 21 when the urologist said, “Your prostate feels irregular, we need to do a biopsy,” and left me in the room alone to get ready, a stab of fear went through my heart. I had no Bible with me, but I had my memory. I prayed and called to mind the promises of God. And Christ came by his word with the sweetest peace, and I almost fell asleep on the table before the doctor came back.

And that’s the way we have walked together since then. Word, prayer, peace. He has come to me in 2 Corinthians 1:8-9, “For we do not want you to be ignorant, brothers, of the affliction we experienced in Asia. For we were so utterly burdened beyond our strength that we despaired of life itself. Indeed, we felt that we had received the sentence of death. But that was to make us rely not on ourselves but on God who raises the dead.” Among the thousands of good things God is doing through this cancer, I know one of them beyond the shadow of a doubt: it is to make me rely less upon myself and more upon God. That is crystal clear. I thank God for this mercy.
He has come to me in 1 Thessalonians 5:9-10, “For God has not destined us for wrath, but to obtain salvation through our Lord Jesus Christ, who died for us so that whether we are awake or asleep we might live with him.” John Piper is not destined for wrath, Christ died so whether I died or live, I live with him. What a great salvation we have! Do you have this?
He has come to me in Psalm 4:7-8, “You have put more joy in my heart than they have when their grain and wine abound. In peace I will both lie down and sleep; for you alone, O Lord, make me dwell in safety.” I thank God for the gift of peace and sleep. It has come every night.
Finally, he has come to me in today’s text: Death is swallowed up in victory because of Christ. Therefore, be steadfast, immovable, and work your fanny off for Christ and his kingdom. I said to the elders, “Settling it in your mind and heart by grace that Christ is real is a wonderfully energizing thing.”
That’s what the “therefore” of verse 58 means. Know the Christ who conquered your death, and know how he did it—read that, memorize that—and then pray, and God will give you peace and strength and a passion for his cause in the world. I am deeply thankful for your prayers. "*

Taken from:
http://www.desiringgod.org/library/sermons/06/010806.html