Understanding the process of citing is a necessary condition for the use of citations in research evaluation. Citations can only be used wisely in these evaluations, if the user is informed about the basic elements of the process and knows the relevant underlying factors. In this study, we introduce a model for explaining citations in scholarly publications. The model is composed of three major elements, including the context of the cited document, pathways from selection to citation of documents, and the context of the citing document. The model is simply designed to include only a few major and minor elements in order to be clear and understandable, but the elements are explained in great detail in this study. With the model, which has its roots in available citation theories, recent studies in bibliometrics on factors influencing citations and citation context are reviewed and synthesized to gain insights into the process of citing. The model can be used to understand the process of citing and delivers basic information for the proper application of citations in research evaluation. The model also reveals gaps in empirical research on citations.