This article outlines a study into Quaker attitudes and behaviours in relation to the testimony of abstinence and moderation and that regarding gambling and speculation. The background to the Quaker testimonies is summarised, and relevant research in the substances/gambling fields about denominational influences on personal behaviours is briefly outlined. The questions raised by recent Quaker scholarship represented are considered, and the study results are outlined in relation to the theory of Quaker double-culture (Dandelion 1996; Dandelion and Collins 2008) and the suggestions of Scully regarding virtue ethics among Quakers (2002, 2008). It is suggested that whereas the liberal belief culture (Dandelion 1996, 2008) and the spiritual/belief diversity within Quakerism (Pilgrim 2008) have some fragmenting effects theologically, in relation to these testimonies, these diversifying elements are counter-balanced by core (deontological) values. These values are spiritually based and widely held among Friends, and are perceived as being specifically Quaker. It is argued that diversifying and unifying factors are thus held in tension in a way that has some distinctive effects, both in terms of individuals and in relation to the denominational profile. It is further argued that the results of this balance are largely benign in terms of substance using and gambling behaviours, and that this may have useful applications beyond a Quaker context.