The only way to learn strong faith is to endure great trials.

From 1 Peter 1:6-7:  “ In this you rejoice, even if now for a little while you have had to suffer various trials, so that the genuineness of your faith—being more precious than gold that, though perishable, is tested by fire—may be found to result in praise and glory and honor when Jesus Christ is revealed.”

German-born George Muller (1805-1898) was a Christian evangelist.  Later in his life, he and his wife spent 17 years involved with missionary travel throughout the world.