The ruin of a man's teaching comes of his followers, such as having never touched the foundation he has laid, build upon it wood, hay, and stubble, fit only to be burnt. Therefore, if only to avoid his worst foes, his admirers, a man should avoid system. The more correct a system the worse will it be misunderstood; its professed admirers will take both its errors and their misconceptions of its truths, and hold them forth as its essence.

The World of George Macdonald: Selections from His Works of Fiction (ed. Shaw, 1978)