In November, 1844, I began to pray for the conversion of five individuals. I prayed every day without a single intermission, whether sick or in health, on the land or on the sea, and whatever the pressure of my engagements might be.
Eighteen months elapsed before the first five was converted. I thanked God and prayed on for the others.
Five years elapsed, and then the second was converted. I thanked God for the second, and prayed on for the other three.
Day by day I continued to pray for them, and six years passed before the third was converted. I thanked 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 hour or day in which they were offered has been praying day by day for nearly 36 years for the conversion of these individuals, and yet they remain unconverted. But I hope in God, I pray on, and look yet for the answer. They are not converted yet, but they will be."
This was the faith that carried him through every straitened place. He met emergencies by asking and in due time God supplied whatever the need might be.
Those prayers? You ask. In 1897, those two men, sons of a friend of Mr. Muller’s youth, were not converted, after he had entreated God in their behalf for 52 years daily. But after his death God brought them in the fold.
George Muller by Basil Miller pg. 146