"In what cases friendship ought to yield to gratitude, or gratitude to friendship. in what cases the strongest of all natural affections ought to yield to a regard for the safety of those superiors upon whose safety often depends that of the whole society; and in what cases natural affection may, without impropriety, prevail over that regard; must be left altogether to the decision of the man within the breast, the supposed impartial spectator, the great judge and arbiter of our conduct."
— Smith, Adam (1723-1790)
(text from http://www.econlib.org, VI.ii.25; cf. pp. 226-7 in Liberty Fund ed.)
Text checked against The Theory of Moral Sentiments; or, an Essay Towards an Analysis of the Principles by Which Men Naturally Judge Concerning the Conduct and Character, First of Their Neighbours, and Afterwards of Themselves. To Which Is Added, A Dissertation on the Origin of Languages. by Adam Smith, LL. D. Fellow of the Royal Societies of London and Edinburgh; One of the Commissioners of His Majesty's Customs in Scotland; and Formerly Professor of Moral Philosophy in the University of Glasgow. The Sixth Edition, With Considerable Additions and Corrections. In two volumes. (London: Printed for A. Strahan; and A. Cadell in the Strand; and W. Creech, and J. Bell & Co. at Edinburgh, 1790). <Link to ESTC>