Shall we make a new rule of life from tonight: always to try to be a little kinder than is necessary?

J. M. Barrie (1860-1937) Scottish novelist and dramatist [James Matthew Barrie]

The Little White Bird, ch. 4 “A Night-Piece,” Scribner’s Magazine, Vol. 32 (1902-08)
    (Source)

This portion of the serial is in ch. 4 of the fully collected novel (1902).