Evangelist George Verwer has revealed he is suffering from Sarcoma cancer.
The founder of Operation Mobilisation says it could be a long term illness but that God may take him at any time.
In an update to supporters, he asked that people don't pray for his healing.
"Please ask people not to pray for total healing as I really am looking forward to heaven," he said. "Ask for prayer for grace for the rough journey that daily will be ahead."
New Jersey born Verwer founded Operation Mobilisation in 1961 as a tool to spread God's word across the world.
The charity now operates in over 110 different countries with evangelists committed to sharing the Bible with all.
Speaking about his illness, Verwer said: "While in hospital, I had a powerful experience with God, in which all burdens for ministry and wrestling with global suffering has been lifted.
"God assured me that I’ve done my part and I need to leave the rest with others and Jesus. In many ways, I feel 85 is too long to live when so many of my friends have died but the Lord has that in His hands. It looks like I will be around a while, but the road to the door looks rough. That’s where I would appreciate prayer."
Verwer says he will spend the time that he has left raising funds for evangelism projects.
He's also asked supporters to keep the nation of India as a priority for prayer and giving.