When Jesus came the first time, predicted by Daniel in his prophecy found in Daniel 9:24-27, He also "cleansed the sanctuary"
His second coming is predicted in Daniel 8:44, when He will cleans the sanctuary a second time.
Why does the sanctuary need to be cleansed for the first and second coming?
Because humanity falls into sin so much prior to each coming. The cleansing of the sanctuary brings with it a new Creation, as attested by Paul in 2 Cor 5:17 and other places, for His first coming, and as attested by the phrase "new heaven and a new earth" for Hos second coming.
