'"'In November 1844, I begain to pray for the conversion of five individuals. I prayed every day without one single intermission, whether sick or in health, on the land or on the sea, and whatever the pressure of my enegagements might be. Eighteen months elapsed before the first of the five was converted. I thanked God and prayed on for the others. Five years elapsed, and then the second was converted. I thanked God, and prayed on for the other three. Day by day I continued to pray for them, and six more years passed before the third was converted. I thnaked God for the three, and went on praying for the other two. These two remained unconverted. The man to whom God in the riches of His grace has given tens of thousands of answers to prayer, in the self-same day or hour in which they were offered, has been praying day by day for nearly thirty-six years for the conversion of these two individuals, and yet they remain unconverted; for next November it will be thirty-six years since I began to pray for their conversion. But I hope in God, I pray on, and I look yet for the answer.
Therefore, beloved brethren and sisters, go on waiting upon God, go on praying; only be sure you ask for things that are according to the mind of God, for He does not desire the death of the sinner. This is the revelation God has made of Himself - "Not willing that any should perish, but that all should come to repentance." Go on, therefore, praying; expect an answer, look for it, and in the end you will praise God for it."
Of the two individuals still unconverted at the time of this sermon, one became a Christian before Muller's death and the other a few years later.'
George Muller in Roger Steer, George Muller, p.193.