The man who sometimes misleads from mistake, however, is widely different from him who is capable of wilfully deceiving.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“Though this involuntary falsehood may frequently be no mark of any want of veracity, of any want of the most perfect love of truth, it is always in some degree a mark of want of judgment, of want of memory, of improper credulity, of some degree of precipitancy and rashness. It always diminishes our authority to persuade, and always brings some degree of suspicion upon our fitness to lead and direct. The man who sometimes misleads from mistake, however, is widely different from him who is capable of wilfully deceiving. The former may safely be trusted upon many occasions; the latter very seldom upon any. Frankness and openness conciliate confidence.11 We trust the man who seems willing to trust us. We see clearly, we think, the road by which he means to conduct us, and we abandon ourselves with pleasure to his guidance and direction.” source