Lk 16:19-31 is a good reference to what happens to our spirit when we die - either Heaven or Hell...
"There was a rich man who was clothed in purple and fine linen and who feasted sumptuously every day. And at his gate was laid a poor man named Lazarus, covered with sores, who desired to be fed with what fell from the rich man's table. Moreover, even the dogs came and licked his sores. The poor man died and was carried by the angels to Abraham's side. The rich man also died and was buried, and in Hades, being in torment, he lifted up his eyes and saw Abraham far off and Lazarus at his side. And he called out, 'Father Abraham, have mercy on me, and send Lazarus to dip the end of his finger in water and cool my tongue, for I am in anguish in this flame.' But Abraham said, 'Child, remember that you in your lifetime received your good things, and Lazarus in like manner bad things; but now he is comforted here, and you are in anguish. And besides all this, between us and you a great chasm has been fixed, in order that those who would pass from here to you may not be able, and none may cross from there to us.' And he said, 'Then I beg you, father, to send him to my father's house-- for I have five brothers--so that he may warn them, lest they also come into this place of torment.' But Abraham said, 'They have Moses and the Prophets; let them hear them.' And he said, 'No, father Abraham, but if someone goes to them from the dead, they will repent.' He said to him, 'If they do not hear Moses and the Prophets, neither will they be convinced if someone should rise from the dead.'" (ESV)
Saul and the Witch of Endor is another passage. This one deals with a supposed ghost appearance...
Then Saul said to his servants, "Seek out for me a woman who is a medium, that I may go to her and inquire of her." And his servants said to him, "Behold, there is a medium at En-dor." So Saul disguised himself and put on other garments and went, he and two men with him. And they came to the woman by night. And he said, "Divine for me by a spirit and bring up for me whomever I shall name to you." The woman said to him, "Surely you know what Saul has done, how he has cut off the mediums and the necromancers from the land. Why then are you laying a trap for my life to bring about my death?" But Saul swore to her by the LORD, "As the LORD lives, no punishment shall come upon you for this thing." Then the woman said, "Whom shall I bring up for you?" He said, "Bring up Samuel for me." When the woman saw Samuel, she cried out with a loud voice. And the woman said to Saul, "Why have you deceived me? You are Saul." The king said to her, "Do not be afraid. What do you see?" And the woman said to Saul, "I see a god coming up out of the earth." He said to her, "What is his appearance?" And she said, "An old man is coming up, and he is wrapped in a robe." And Saul knew that it was Samuel, and he bowed with his face to the ground and paid homage. (1Sa 28:7-14, ESV)
Notice what the woman said that she saw - "a god" - very interesting.