Acts 21:26 describes Paul entering the temple to give notice 'concerning the completion of the days of purification' (hagnismou). This refers to the Nazirite vow ritual detailed in Numbers 6, involving a week-long purification process. The noun derives from 'hagnizō' (to purify), common in Septuagintal contexts for ritual cleansing. Paul's participation in this Jewish ritual demonstrates his continued adherence to Torah when among Jews—living out his missionary principle of becoming 'all things to all people.' The purification required both time and public declaration at the temple.