“This world” is what we feel right now, and “the world to come” (Olam HaBa) is our next state. Everything becomes revealed according to one’s desire. One’s desire can either be changed naturally, by means of Reshimot that make it more egoistic; or it can be corrected by one’s work with the group and the Surrounding Light.
If I don’t correct myself, then all the gates to the spiritual sensation will remain closed to me. I can’t feel the spiritual world without preparing my desires and Kelim for it, without correcting egoism to bestowal. That is how I can open the gates!
Every person who goes to that world without having attained the secrets of the Torah (which is possible only by studying Kabbalah in order to receive Light into one’s corrected desires), even on account of many good deeds (the way people think in this world), is banished from the gates of the Upper World (meaning, that person has no opportunity to feel and enter the eternal world).
On the spiritual path, this happens on every step of the way when we go from one state to another. You can only advance by revealing secrets – that which is concealed from you right now. Everything happens inside your desire. Your current desire and sensation are called “this world,” and a more corrected desire and sensation are called “the world to come.”