The general function of the ritual described in Leviticus 16 is well known: it removes the impurities and the sins – unintentional and intentional – of the Israelites. A number of factors, however, contribute to obscure both some of the details about how the ritual operates and how it is conceived within the broader priestly ideology. This paper will attempt to clarify some issues relating to this text, with particular attention to the use of prepositions therein.