2 Corinthians 4:17-18 (New International Version)

17 For our light and momentary troubles are achieving for us an eternal glory that far outweighs them all. 18 So we fix our eyes not on what is seen, but on what is unseen, since what is seen is temporary, but what is unseen is eternal.

From BibleGateway.com: http://www.biblegateway.com/passage/?search=2 corinthians 4:17-18&version=NIV