1) To the man on the street, the concept of “holiness” belongs in the domain of the spiritual elite. The Dalai Lama, for example, is called “His Holiness” – the expectation is that someone who is “holy” will be living in a monastery in Tibet, not be riding the subway and be walking the streets of Manhattan. That’s what makes the opening of our parsha so remarkable. “Dabeir el kol adas Bnei Yisrael… kedoshim te’hiyu.” Davka here, when speaking of kedusha/holiness, the Torah demands that Moshe gather all of Klal Yisrael to make sure every single individual gets the message. That message is twofold: 1) yes, there is a lofty level of kedusha that only the spiritual elite can reach, but there are also levels of kedusha that each and every one of us can incorporate into our own lives; 2) even if we never reach those lofty levels, we can at least look to them as guides to the path we should be following. Even the GR”A claimed that he did not get beyond the lower rungs of positive midos described by the Mesilas Yesharim. So what are we doing when we learn such a book? We are setting our sights on where we should be headed, even if we never get there.
2) The meforshim (see the very nice Ohr haChaim) discuss why the Torah mentions “u’netatem kol eitz ma’achal” as a preface to the mitzvah of orlah. The Torah could just tell us not to eat the fruit of a tree during the first three years without talking about planting -- obviously you have to plant a tree to have fruit. The Midrash quotes the pasuk of “acharei Hashem Elokeichem teileichu” and asks how it is possible to follow G-d. The gemara in Sota answers that the pasuk means to follow the midos of G-d – just as he is rachum, so too we must show rachmanus; just as he is gomeil chassadim, so too must we be gomeil chassadim, etc., The Midrash here adds an additional element: just as G-d planted, “Vayita…gan b’Eden,” so too, we should be like him and plant. “U’nitatem…” is not just the circumstances under which the issur of orlah applies -- it's a command in its own right, a way of being more like G-d. The Tanchuma writes that Hashem said that even if we find Eretz Yisrael filled with every good thing, we shouldn’t just sit back and enjoy that bounty, but we must plant. Why plant if there is no need? Our Midrash provides the answer – because planting is a way of becoming more like G-d.
The Midrash also connects “u’nitatem” to the pasuk of “eitz chaim hi la'machazikim bah.” Our pasuk is talking about planting real trees that produce real fruit; the "eitz chaim" is a metaphorical tree, the tree of Torah -- what does one thing have to do with the other? The Sefas Emes explains that there are physical roots and spiritual roots. When a Jew plants a tree in Eretz Yisrael, the goal is not just to set tree roots into the ground -- the goal should be to better the world, the goal should be to bring Hashem's plan, not just dates and figs, to fruition.