Perek 1, Mishna 2
Shimon Ha-tzaddik was one of the last survivors of the Great Assembly. He used to say: The world is based on three things; the Torah, serving God and active loving-kindness.
The Mishna as written seems fairly simple, Shimon Ha-tzaddik was the last of the Anshei Kenesset Ha-gedolah, and he said that the world stands on Torah, avoda (service), and gemilut chasadim (or gemah - acts of kindness). Continuing his interest in the passage of the generations, Maharal notes that Shimon received special mention because he lived long enough to meet a new generation, with new needs. While the previous dicta being moderate in judgement and so on were relevant to that generation, in the generation that Shimon survived into, a new credo was necessary. Maharal recognizes the importance of context in the teaching of Torah he's not claiming that Shimon articulated new principles (in fact, at the end of this Mishna, we'll see that he actually thought Shimon said much the same thing as the other Anshei Kenesset haGedolah), just that he expressed them in the fashion most appropriate to the generation he was in.
A second question raised by the Mishna is why these three items in particular are the necessary pillars of the world, and here Maharal has several answers:
1) These three things ensure perfection of the human being. Other creatures were created fundamentally good (individual members of any group may be bad, but the group as a whole apples, cows, etc. were good). This explains why, at the conclusion of their creation, Hashem saw that it was "good." (Genesis 1;12). Man, however, needs to be perfected in three areas in terms of himself, in terms of his relationship with God, and in terms of his relationship with his fellow-man. The three elements named here perfect man in all those ways: Torah perfects man's intellect by training it with the Divine wisdom (this constitutes a negation of the value of an untrained human intellect to be worthwhile, man's intellect needs the training of Torah), avoda (usually sacrifices, although Maharal believes mitzvot generally function this way) helps perfect our relationship with God (or at least focus on it appropriately), and gemah, perfect our relationships with other humans.
Note that others had connected these three pillars to actions between man and Godc. In Maharal's view, however, these acts are meant to help perfect human beings. Rambam expressed a similar idea. However, he believed the "world" which stands on these three things is the world of the human soul. By contrast, Maharal that human perfection (or our continued striving towards it) is vital to the continued health of the world as a whole, since the whole world was only created as an environment in which humans could work towards perfection.
These three areas of perfection help Maharal explain two seemingly extraneous ideas. First, he says, this categorization explains why there are three commandments a Jew must die for rather than transgress murder, idolatry, and sexual immorality. The Talmud derives these ideas either from verses, or logic (it's impermissible to kill someone else to save one's own life, because that involves judging one life to be superior to another, an estimation we are not allowed to make). Maharal suggests that each of these transgressions corresponds to one of these perfection's Avoda Zarah contradicts one's avoda, worship of God, sexual immorality is a completely physical act (the Talmud suggestively calls it a ma'aseh behemah) contradicting Torah, which is completely intellectual, and murder is quite obviously the opposite of kindness. When violating these three laws, then, a person is distancing himself from perfection, moving in the wrong direction. The ordinary value of life thus cannot operate in that situation.
In the course of his discussion, Maharal claims that the generation of the Flood was not destroyed until they violated all three of these commandments. Interestingly, though, he does not claim that they committed murder, but hamas, theft of some sort. To contradict gemah completely, an individual has to commit murder, but if an entire society commits hamas, that too qualifies as an inversion of gemah, one of our human responsibilities. Perhaps we can infer that Maharal would think that communal hamas would be categorized as yehareg ve'al ya'avor.
2) These three items protect our connection to God Torah by making the world a place worthy of God's presence, avoda by maintaining the connection with God even at times of sin, and gemah by providing a basis for God to grant us the kindness of a livelihood (which Maharal calls the greatest kindness there is).
3) The three values are also representative of the three Patriarchs. Avraham most clearly put the principle of gemah into action through his hakhnassat orkhim, welcoming guests. Yitzhak is the epitome of avoda, having himself almost become a sacrifice to God. Yaakov, the "ish tam yoshev ohalim, the innocent man sitting in tents" is the paragon of study. Thus, while Shimon Ha-tzaddik lists these three elements as the elements that maintain the world, Maharal suggests that our Patriarchs serve as examples of each value as a lasting national legacy.
4) Maharal suggests that each of these values reflects a different base element of the world. Remember that until the late 18th century, the world was thought to be made up of four elements aearth, wind, fire, and water. Other than earth, the elements had a heavenly aspect to them (there are mayim elyonim, water above the firmament; clearly air or wind is above the earth, and so is fire). Torah corresponds to spirit (wind), Avoda to fire, (sacrifices are generally burned on the fire of the altar) to fire, and kindness to water (the connection is more obscure here, but Maharal has some references to acts of kindness as being water-like). Regardless of how he draws the connection, in this interpretation keeping Torah, avoda, and gemah contributes to continued existence of the world in a much more direct way than earlier explanations, since upholding these three values strengthens the smooth functioning of those elements.
5) Last, Maharal suggests that Shimon's three elements are in fact equivalent to the three items listed by the Anshei Kenesset ha-Gedolah. Avoda and justice are connected to each other, as symbolized by the placement of the Sanhedrin right next to the Temple. Torah is what allows one to create students. Finally, Gemah is a type of seyag - since we do not adhere to seyagim out of legal obligation, in the same fashion that we perform acts of kindness with no specific legal obligation. More interesting than the actual content of the connection between Shimon Ha-tzaddik, though, is the attempt by Maharal to create continuity of message he recognizes that although Shimon had to phrase his ideas differently for a different generation, the content of that message was the same as the previous one.
Since Maharal doesn't differentiate among the various ideas he puts forward, we are left to assume that he sees truth in each of them, a conclusion that leads from this Mishna alone to an interesting perspective of the world. According to Maharal, the world was created as a setting for humans to perfect themselves in three areas within themselves, in their relationship with God, and with other humans. If they fail in that endeavor, the rest of the world becomes meaningless, as does life itself. In perfecting themselves, they also make the world a place ready for the Divine presence (version number 2). Beyond that, the Patriarchs set an example for us in each area, personifying the different components of the world's good health. (Others have noted this in other contexts, but it bears repeating Avraham, Yitzchak, and Yaakov, are the Avot as a unit. Each has his particular strengths, but it is as a unit that they present a whole legacy for the Jewish people; once that legacy had been created, it was time for the tribes to be born and the nation to start.) The point about the elements (air, fire, and water) reflecting Torah, avoda, etc., interjects a physical reality into our spiritual experiences. One could, as a believing Jew, think that the physical and spiritual are separate realms, each with its own importance. In such a view, for example, when the Torah promises exile for not observing shemitta, the seventh Sabbatical year, that is a punishment from God without any real connection to the action. God sees us violate a commandment, and administers a punishment. Others believe (and Rambam quite probably belongs in this group) that the world was created in a way that allows punishments to extend almost naturally from sins. This view implies a much stronger connection between our supposedly purely spiritual actions and the world. That Maharal aligned the physical elements to Torah, etc. suggests that he believed in such a connection. Finally, his finding a way to make the first Mishna and the second say similar things leads one to conclude that he sees the truths of those generations as extremely close to each other in content, yet phrased differently for different eras.