Jesus promises his followers that he's building each of them a mansion in heaven, and he just needs to go now for a bit to check on the construction progress. But he'll be right back! Thomas is the only one smart enough to doubt him and asks how they'll know where to find him after the apocalypse. Jesus has a snappy rejoinder prepared: I am the way, the truth, and the life: no man cometh unto the Father, but by me. (v. 6)
But Thomas has managed to sow the seeds of doubt in Philip as well, who wants to see this father before he'll trust Jesus to go away on a 'business trip.' Jesus insists that he and god are one and the same and makes an even greater claim: He that believeth on me, the works that I
do shall he do also; and greater works than these shall he do (v. 12). He then promises to do anything they ask of him, as long as they keep the commandments. Go ahead, try this one at home. He also promises to either come back himself or send someone to comfort them forever, because, see, by the time this gospel was written, it was pretty clear that nobody was coming for us any time soon.
Other facts about the resurrection: now only believers will see it. A Judas, apparently not that one, asks how he'll show himself to them only, and Jesus replies that people who love him will obey him, and both he and his dad will move in with them. People who love him will not obey him but on the plus side, they won't have any freeloading houseguests either.
A note about the comforter: it will be the holy ghost. He also promises world peace and freedom from worry or fear. He then promises to shut up, though we still have 7 chapters to go in this gospel, so I don't have faith, and then tells them it's time to meet his destiny.