Likutei Moharan 25:8/ליקוטי מוהר"ן כ״ה:ח׳

18. The following relates to section 3:

2And know! no two people are alike…. Therefore, when a person wants to ascend from his level to an even higher level, then the person on the higher level goes and moves on to a st ill higher level. [Rebbe Nachman] then said the following:

3This is the concept of lifting up, that which one person lifts and raises up his friend. By virtue of the person on the lower level ascending from level to level, through this he raises and lifts up his friend who is on the higher level so that he ascends to an even higher level. Likewise his friend’s friend, who is even higher than his friend—he has ascended even higher. And so it is, higher and higher, because it is impossible for two people to be on the same level, as above.