Is it possible to get into heaven, but then be cast out at a later date? People struggle to enter Heaven, but what guarantees you that once you get there you won't be cast out from Heaven? In the Bible there is no guarantee about that. What will prevent you from making bad mistakes there?
In the parable of the Rich man and Lazarus, Jesus says no:


  And he cried out, ‘Father Abraham, have pity on me. Send Lazarus to dip the tip of his finger in water and cool my tongue, for I am suffering torment in these flames.’ Abraham replied, ‘My child, remember that you received what was good during your lifetime while Lazarus likewise received what was bad; but now he is comforted here, whereas you are tormented. Moreover, between us and you a great chasm is established to prevent anyone from crossing who might wish to go from our side to yours or from your side to ours.’  (Luke 16:24-26 NABRE)


Now, Heaven here is the "bosom of Abraham", but if this parable has anything to do with us (and all scripture has something to do with us) I doubt Jesus is only talking about Heaven in the moral sense here.