Rabban Yochana ben Zakkai observed that he had five principal students, and each one had a unique quality that was rooted in a one of the five element

Chapter 2: Mishna 11: Part 1
He used to enumerate their praises. Eliezer ben Horkonus [is like a] cemented well which does not lose [even] a drop [of water]. Yehoshua ben Chanania -- praiseworthy is she who gave birth to him. Yossi HaCohen is a "chasid" (a pious one). Shimon ben Nethanel is one who fears sin. Elazar ben Arach is a flowing spring that surges forth. (As I wrote when we began the previous Mishna, the Maharal's explanations do not follow the order of the Mishnayoth. I have inserted the next Mishna at this point, but the beginning of our explanation is a continuation from last week. One question that was not yet explicitly answered from the previous Mishna will be answered now, and we will introduce other questions -- not necessarily in the order that they were asked -- that the Maharal will answer about this Mishna.) (Carried over from the previous Mishna: Didn't Rabban Yochanan ben Zakkai have more than the five students whose praises are enumerated here?! Furthermore...) Why does our Mishna use the language "enumerate ('moneh') their praises" rather than the simpler "informed ('magid') of their praises?" What is the greatness of Yehoshua ben Chanania that is implied in "praiseworthy is she who bore him?" If his greatness was that he was pious, then the same "praiseworthy is she who bore him" could have also been said about Yossi HaCohen! And if his greatness was that he feared G-d, then this description could have been said about Shimon ben Nethanel as well! And if the praise is because of his great wisdom, then it could have also been said of Elazar ben Arach, whose wisdom was praised as a flowing stream constantly surging forth! Rabban Yochana ben Zakkai observed that he had five principal students, and each one had a unique quality that was rooted in a one of the five elements of the human being. Therefore he enumerated their praises. The word "enumerated" is used, implying the exhaustive nature of the these five attributes, since these praises encompass each of the five elements of the human being. (The Maharal points out many times that when a number is used, it communicates the exhaustive nature of the list that is being presented. The Rabbis shouldn't need to provide the number of components in a list, since we know how to count for ourselves. Telling us the number communicates a conceptual principle, rather than a mathematical summary.) Another implication of the word "enumerate" ('moneh') is that each one stands independently, which is the case of these five virtues. Rabban Yochana ben Zakkai began with Rebbe Eliezer ben Horkonus, saying about him that he was a cemented well which does not lose a drop [of water]. This is an acclamation in the area of the nefesh. Memory is an attribute of the nefesh, and it is through this vehicle that one is able to acquire and retain wisdom. The ability to remember what one has learned indicates that the individual is able to rise above the material ("chomer") dimension of his existence. For "chomer" (matter) has the characteristic of being subject to change, influenced by environmental circumstances due to its instability. Something which transcends the limitations of the chomer isn't limited by the instability inherent in matter which causes it to be in a state of constant change. So by saying that Eliezer ben Horkonus was like a cistern which loses no water, it means that his nefesh is imbued with a transcendent energy, a stability that resists variation, which is the ideal state of the nefesh. It is this desired state of stability which is implied when we use the word "milui," sated, to refer to the nefesh, as it is written (Koheleth 6:7) "Also the nefesh will not be sated." The nefesh grasps and retains a connection to things, due to the fact that it does not have limitations of matter. It is to communicate this attribute that Rebbe Eliezer is called a cistern that doesn't lose a drop. What he receives is retained. Then it is said about Yehoshua ben Chanania "praiseworthy is she who gave birth to him." As we have written, the energy of the nefesh ("koach hanefesh") has to have a material medium through which it can manifest itself. This is the "chomer," the material dimension. Exalting the woman who bore him implies a purity in his chomer, in the material dimension. If his mother didn't have a dimension of purified chomer, it would not be possible for the child to have this purity of chomer. The mother is viewed as being the determining factor in the quality of the chomer of a child (see Nidah 31a) due to her greater connection to the physical world. (We have written extensively on this in Chapter One, Mishna 5.) We find Rebbe Eliezer ben Horkonus and Rebbe Yehoshua ben Chanania paired to together throughout the Talmud, and this is represented here. For Rebbe Eliezer ben Horkonus embodies excellence of the nefesh, which is transcendent, while Rebbe Yehoshua ben Chanania embodies excellence of the chomer, which serves as a carrier of the nefesh in the material world