Where does it say in the Bible that you can only be saved during your life and not once you have died?

For instance, you die and are waiting in purgatory, during this time period you figure out that everything you struggled to believe on Earth is actually factual. You are truly repentant for your actions during your life and you beg God for mercy. Is the loving savior that died for our sins just going to throw you in Hell anyways? Or is he going to be merciful and accept that you have come to acknowledge him? What if you are in Hell and this happens? What if you are in heaven and detest God, will you be punished like Lucifer was?