President Eyring said the following on adversity:

"I have seen faith and courage come from a testimony that it is true that we are being prepared for eternal life. The Lord will rescue His faithful disciples. And the disciple who accepts a trial as an invitation to grow and therefore qualify for eternal life can find peace in the midst of the struggle."

His talk on Adversity in it's entirety;
http://lds.org/general-conference/2009/04/adversity?lang=eng&query=thou+will+endure+well