(Josh Waxman from the Parsha blog pointed this out in a recent post. I would like to put it here to see if there is any response to it.) It says in Sanhedrin Daf 24a מאי בבל א"ר יוחנן בלולה במקרא ...
The last perek of Sanhedrin lists some people who have no share in Olam Haba. Other people who forfeit their share are discussed in the answers to this question: No Olam Habah for these? My question ...