2 Corinthians 5:7
New American Standard Bible
7 for we walk by faith, not by sight—
You probably know the illustration of Fact, Faith and Experience, [as they were] walking along the top of a wall. Fact walked steadily on, turning neither to right nor left and never looking behind. Faith followed and all went well so long as he kept his eyes focused upon Fact; but as soon as he became concerned about Experience and turned to see how he was getting on, he lost his balance and tumbled off the wall, and poor old Experience fell down after him.