The diary of George Mueller, Christian social reformer from the Victorian era, chronicles his devotion in prayer:

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, on the sea, and whatever the pressure of my engagements 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 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.

Thirty-six years later he wrote that the other two, sons of one of Mueller's friends, were still not converted. He wrote,

But I hope in God, I pray on, and look for the answer. They are not converted yet, but they will be.

In 1897, fifty-two years after he began to pray, these two men were finally converted, after he died. Mueller understood what Jesus meant when he told his disciples "that they should always pray and not give up."