Matthew 22

When a certain king finally invites guests off of the street after those previous bidden refused to come not being worthy -

"And when the king came in to see the guests, he saw there a man which had not on a wedding garment:
12 And he saith unto him, Friend, how camest thou in hither not having a wedding garment? And he was speechless.
13 Then said the king to the servants, Bind him hand and foot, and take him away, and cast him into outer darkness; there shall be weeping and gnashing of teeth.
14 For many are called, but few are chosen."  (Matthew 22:11–14)

Even though the man was invited off of the streets, he still had an obligation to dress for the event.  In my mind, this is the same as Christ's invitation to come follow him.  But that still requires us to repent and live according his gospel and law.