26 We do not, however, wish to give the impression that this studied simplicity in imparting instruction does not require labor and meditation - on the contrary, it demands both more than any other kind of preaching. It is much easier to find a preacher capable of delivering an eloquent and elaborate discourse than a catechist who can impart a catechetical instruction which is praiseworthy in every detail. No matter what natural facility a person may have in ideas and language, let him always remember that he will never be able to teach Christian doctrine to children or to adults without first giving himself to very careful study and preparation. They are mistaken who think that because of inexperience and lack of training of the people the work of catechizing can be performed in a slipshod fashion. On the contrary, the less educated the hearers, the more zeal and diligence must be used to adapt the sublime truths to their untrained minds; these truths, indeed, far surpass the natural understanding of the people, yet must be known by all - the uneducated and the cultured - in order that they may arrive at eternal happiness.
Source: Acerbo Nimis (Vatican.va)