Read Luke 12:36 Using Other Translations
And ye yourselves like unto men that wait for their lord, when he will return from the wedding; that when he cometh and knocketh, they may open unto him immediately.
and be like men who are waiting for their master to come home from the wedding feast, so that they may open the door to him at once when he comes and knocks.
as though you were waiting for your master to return from the wedding feast. Then you will be ready to open the door and let him in the moment he arrives and knocks.