The prologue to the late-fourteenth-century sermon collection John Mirk’s Festial is clear in its target audience: those clerics ‘defaute of bokus and sympulnys of letture’ whose shortcomings, both in knowledge and vocational aptitude, he sought to remedy. While Mirk here directs his anxieties towards the behaviour of his colleagues, he does so with the hope that this will in turn improve the level and quality of teaching provided to their parishioners. By examining the strategies Mirk puts in place to counter the deficiencies he observed, my thesis contributes to the increased interest in the Festial that has followed Susan Powell’s EETS edition of the work in 2009, as well as recent studies of the text by Judy Ann Ford (2006), Beth Allison Barr (2008), Ellen Rentz (2015) and Laura Varnam (2018). It highlights the pedagogic and affective qualities of Mirk’s writing and explores how these made the Festial more than just an instructive text, facilitating lay devotional practice in and beyond the parish space, both by its original audiences and later readers. In Chapter One I use the Festial to situate the exemplum in its parish context. I argue that while exempla have a long and intricate history in rhetoric, preaching manuals included, the prevalence of the device in late-medieval preaching directly corresponds to the pedagogic drive of the Church that was catalysed by the Fourth Lateran Council of 1215. To do so, my thesis builds upon a body of recent, predominantly French, scholarship to propose a definition of the late-medieval exemplum as a didactic tool that is best defined by its rhetorical function. I argue that the delivered context of an exemplum – its speaker, listener(s) and locus - is fundamental to the meaning it conveys and impact it has. Within this framework, I highlight the range of ways in which Mirk used exempla to facilitate a layperson’s individual, often interior, experience of - and response to - his words. In so doing, I establish that the Festial enabled a level of devotional engagement that exceeded the elementary educational expectations of pastoral reform. At a time when texts such as Walter Hilton’s Mixed Life were seeking to satiate the laity’s growing interest in spiritual development, Mirk’s sermons share a similar motivation to provide orthodox ways for a layperson to immerse themselves in their faith. Chapter 2 explores the immediate experience of Mirk’s preaching and how he cultivates an intensely engaging, somatic experience for his parishioners – both increasing their religious understanding and bolstering their faith - through the use of images, material or imagined. Chapter 3 presents the mnemonic and quasi-meditative devices used by Mirk to enable parishioners to sustain a heightened devotional state beyond the walls of the church. Chapter 4 analyses the sense of community created through positive emotion by looking in particular at the sensation of joy as a foretaste of Heaven. Finally, Chapter Five uses the Festial’s manuscript corpus to discern opportunities for, and moments of, independent engagement with one’s faith and the literary resources that fuelled it. By using evidence of contemporary interactions with the Festial, as well as analysis of the textual juxtapositions between the Festial and other works in compilation manuscripts, I propose different ways in which Mirk’s sermons may have been read by the laity. This serves to refine our current perception of the text and opens it up to new approaches.