Claremont, line 148, reported in Bartlett's Familiar Quotations, 10th ed. (1919). Compare: "And learn the luxury of doing good", Oliver Goldsmith, The Traveller, line 22; George Crabbe, Tales of the Hall, book iii; "If to do were as easy as to know what were good to do, chapels had been churches, and poor men’s cottages princes’ palaces", William Shakespeare, The Merchant of Venice, Act i. Sc. 2.https://en.wikiquote.org/wiki/Samuel_Garth