“See Life steadily, see it whole.”
                                        
                                        My special thanks, whose even-balanced soul,
From first youth tested up to extreme old age,
Business could not make dull, nor passion wild:
Who saw life steadily, and saw it whole.
—Matthew Arnold,  "To a Friend" http://whitewolf.newcastle.edu.au/words/authors/A/ArnoldMatthew/verse/strayedreveller/friend.html from The Strayed Reveller, and Other Poems (1849) 
Misattributed