Francis David’s selected sermons were published by the printing press of Gyulafehérvár in 1569. These sermons are structured almost identical: biblical text, summary, lessons and the proper sermon. Most of the sermons, which adhered very strictly to the explanation of the text, were preached probably in the court of John Sigismund, Prince of Transylvania, while others were at services and workshops for priests who came to the religious disputes. As modern readers, we could imagine that bishop Francis David might have held a training course for pastors to prepare them for propagating the antitrinitarian doctrines whenever they had the opportunity. This paper examines to what extent Francis David's sermons can be considered 'miniature encyclopaedias' or 'repositories of useful knowledge' as were the sermons of the 16th century. The study concludes that, although these sermons were delivered in church, they were not addressed to the ordinary people of the congregation, but were intended as a guide for Unitarian clergy.