This quote is attributed to both Lincoln and Max Beerbohm, but no cite to a source, or context, shows up for either in my perfunctory searching. Beerbohm was born in 1872 so arguably he could have said it in some famous context himself, quoting Lincoln, and had the quote attributed to him (he was reasonably renowned for his Wildean propensity for epigrams that makes me think of these Victorians (or Johnson, for that matter) spending an hour or two each day coining witty bon mots, then anxiously waiting for an opportunity to shoehorn them into conversation or print).