What are your retiring from?

So what are you retiring from?  I have heard of pastors retiring but I am not sure why and from what.  I'm still reading George Muller's autobiography and am continually amazed.  God used Muller for so much.  Not only did God use Muller to pastor a church of 1200 people, start schools that taught over 123,000 students, distributed publications by the millions, support numerous missionaries, to build 5 buildings in his orphanage and care for 10,024 orphans before he died, God also brought in 75 million pounds by prayer only and answered 50,000 requests which 30,000 of them were in the same hour or day that they were asked.

Now this is amazing enough but Muller surprises me yet again.  He actually started his overseas mission work at the age of 70.  Most people retire and die soon after at this age but no Muller.  God, by His grace, allowed Muller and his wife to be missionaries from the age of 70-87.  He traveled over 200,000 miles and to 42 countries by boat, horse, foot, wagon and other various means as an elderly man.  Some of the countries include:  England, Scotland, Ireland, America, all over Europe, Canada, Egypt, Palestine, Syria, Turkey, Greece, Germany, Russia, Poland, India, Australia, China, Japan, New Zealand, In his old age in the mission field, he preached 5-6000 times in many languages.  Now that is a good retirement.  All was possible only by the sustaining grace of God but when you have Godly desires to advance the kingdom of Christ, God provides the grace and means to accomplish them.  Retirement should be going to work full time for God.