Whatever you are, be a good one.

William Makepeace Thackeray (1811-1863) English novelist

(Attributed)

Attributed in Laurence Hutton, "A Boy I Knew," St Nicholas Magazine (Mar 1897), where it was originally given as "Whatever you are, try to be a good one." Often attributed to Abraham Lincoln (first recorded in 1946). For more information, see here.